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Free Online Calculators

Accurate, fast calculators for finance, health, math, date & time, and more.

Financial
Financial Calculators
15 calculators
Mortgage Calculator Loan Calculator Auto Loan Calculator Interest Calculator Payment Calculator Retirement Calculator Amortization Calculator Investment Calculator Inflation Calculator Finance Calculator Income Tax Calculator Compound Interest Salary Calculator Interest Rate Calculator Sales Tax Calculator
Health
Health Calculators
9 calculators
BMI Calculator Calorie Calculator Body Fat Calculator BMR Calculator Ideal Weight Calculator Pace Calculator Pregnancy Calculator Conception Calculator Due Date Calculator
Math
Math Calculators
6 calculators
Scientific Calculator Fraction Calculator Percentage Calculator Random Number Generator Triangle Calculator Standard Deviation
Calendar
Date & Time
4 calculators
Conversion
Conversion Calculators
3 calculators
Other Calculators
Other Calculators
10 calculators
Age Calculator Date Calculator Time Calculator Hours Calculator GPA Calculator Grade Calculator Concrete Calculator Subnet Calculator Password Generator Conversion Calculator

Loan Calculator

Formula
M = P × [r(1+r)ⁿ] / [(1+r)ⁿ-1]
M = monthly payment, P = principal
r = monthly rate, n = months
Monthly Payment
$391.32
per month
Total Payment$23,270
Total Interest$3,270
Principal$20,000

How the Loan Calculator Works

A loan calculator helps you estimate your monthly repayment based on the loan amount, interest rate, and repayment period. Whether you're taking out a personal loan, a student loan, or any fixed-term installment loan, this tool gives you an instant breakdown of what you'll owe each month.

Enter the principal (the amount you want to borrow), the annual interest rate offered by your lender, and the loan term in months. The calculator uses the standard amortization formula to give you your fixed monthly payment, total amount repaid, and total interest cost over the life of the loan.

Tips: A shorter loan term means higher monthly payments but less total interest. A longer term lowers monthly payments but increases the total cost. Always compare offers from multiple lenders to find the best interest rate.

Mortgage Calculator

Monthly Payment
$2,201
principal + interest + tax
Principal & Interest$1,904
Property Tax$300
Loan Amount$280,000
Total Interest$405,808

About the Mortgage Calculator

A mortgage calculator helps you estimate your monthly home loan payment, including principal, interest, and property tax. It is one of the most important tools when budgeting for a home purchase, letting you instantly see how much house you can afford.

Enter the home price, your down payment, the annual interest rate, loan term (15, 20, or 30 years), and annual property tax. The calculator breaks down your payment into its components so you can plan your monthly budget accurately.

Key insight: A 30-year mortgage has lower monthly payments but you pay significantly more in total interest compared to a 15-year mortgage. Use this tool to compare scenarios before speaking with a lender.

Compound Interest Calculator

Formula
A = P(1 + r/n)^(nt)
A = final amount, P = principal
r = rate, n = frequency, t = years
Final Amount
$20,097
after 10 years
Interest Earned$10,097
Principal$10,000
Return Rate100.97%

Understanding Compound Interest

Compound interest is interest calculated on both the initial principal and the accumulated interest from previous periods. It is often called the "eighth wonder of the world" because of its powerful effect on long-term savings and investments.

Enter your principal amount, annual interest rate, the number of years, and how frequently interest compounds (daily, monthly, quarterly, or annually). The more frequently interest compounds, the faster your money grows.

Example: $10,000 at 7% annual interest compounded monthly for 10 years grows to over $20,000 — doubling your money without any additional contributions. This is why starting to save early makes such a significant difference.

Auto Loan Calculator

Auto Loan
Calculate your monthly car payment
Formula
Loan = Price − Down − Trade-in
M = Loan × [r(1+r)ⁿ] / [(1+r)ⁿ−1]
Monthly Payment
$454
per month
Loan Amount$23,000
Total Payment$27,240
Total Interest$4,240
Total Cost$32,240

How the Auto Loan Calculator Works

The auto loan calculator helps you determine your monthly car payment based on the vehicle price, down payment, trade-in value, interest rate, and loan term. Understanding your monthly obligation before visiting a dealership gives you significant negotiating power.

Enter the vehicle price, how much you plan to put down, any trade-in value, the dealer's offered interest rate, and your preferred repayment term (24 to 84 months). The calculator shows you the exact monthly payment, total amount paid, and total interest cost.

Tip: A shorter loan term (24–36 months) means higher payments but far less interest paid overall. Longer terms (72–84 months) are more affordable month-to-month but increase your total cost and the risk of becoming "underwater" on the loan.

Interest Calculator

Simple vs Compound
Compare interest types side by side
Formulas
Simple: I = P × r × t
Compound: A = P(1 + r/n)^(nt)
Compound Interest Earned
$2,834
compound total
Simple Interest$2,500
Compound Interest$2,834
Simple Total$12,500
Compound Total$12,834
Extra from Compounding$334

Simple Interest vs Compound Interest

The interest calculator lets you compare simple interest and compound interest side by side. Understanding the difference helps you make smarter decisions when choosing savings accounts, evaluating loans, or comparing investment products.

Simple interest is calculated only on the principal amount — it does not grow over time. Compound interest is calculated on the principal plus all previously earned interest, causing your balance to grow exponentially over time.

Enter the principal, annual interest rate, and time period in years. You can also select the compounding frequency for the compound interest calculation. The results show both outcomes side by side, making it easy to compare.

Payment Calculator

Payment Planner
Find payment, rate, or loan amount
Monthly Payment
$358
per month
Total Payment$17,184
Total Interest$2,184
Principal$15,000

What Is a Payment Calculator?

The payment calculator helps you estimate fixed monthly payments for any type of installment loan. It is useful for personal loans, medical bills, home improvement financing, and any other fixed-term borrowing arrangement.

Input the loan amount, interest rate, and repayment term to instantly see your regular payment amount and the total cost of the loan. The tool uses the standard amortization formula used by banks and lenders worldwide.

How to use it: If a lender quotes you an interest rate, enter it directly. If you want to work backwards — finding out how much you can borrow given a monthly payment you can afford — try adjusting the principal amount until the payment matches your budget.

Retirement Calculator

Retirement Nest Egg
Project your retirement savings
Projected Savings at Retirement
$1,842,000
in 35 years
Total Contributions$235,000
Investment Growth$1,582,000
Inflation-Adjusted Value$655,000
Monthly Income (4% rule)$6,140

Plan Your Retirement with This Calculator

The retirement calculator estimates how much money you will have saved by the time you retire, based on your current savings, monthly contributions, expected return rate, and years until retirement. It is an essential tool for long-term financial planning.

Enter your current savings, how much you plan to contribute each month, the expected annual return on your investments, and the number of years until you retire. The calculator uses compound growth to project your future retirement fund.

The power of time: Starting retirement contributions 10 years earlier can more than double your final savings. Even small increases in monthly contributions make a dramatic difference over 20–30 years due to compound growth. The earlier you start, the less you need to save each month to reach the same goal.

Amortization Calculator

Amortization Schedule
See principal vs interest over time
Monthly Payment
$1,264
per month
Total Interest$255,088
Total Payment$455,088
Payoff DateMay 2055
Interest Savings (extra)$0

Understanding Loan Amortization

Amortization is the process of paying off a loan through regular scheduled payments. Each payment covers both interest and a portion of the principal. In the early stages of a loan, most of your payment goes toward interest — over time, more of it reduces the principal balance.

The amortization calculator generates a full repayment schedule showing exactly how each monthly payment is divided between interest and principal, and how your remaining balance decreases over time.

This tool is particularly useful for mortgages, auto loans, and personal loans. Understanding your amortization schedule helps you identify the best time to make extra payments (early in the loan) to save the most interest.

Investment Calculator

Investment Growth
Project returns with regular contributions
Formula
FV = P(1+r)ⁿ + PMT × [(1+r)ⁿ − 1] / r
P = initial, PMT = monthly contrib
Future Value
$165,048
after 20 years
Total Invested$58,000
Total Returns$107,048
Return on Investment184.6%

How the Investment Calculator Works

The investment calculator projects how your money will grow over time when invested at a given rate of return. It accounts for an initial lump sum, regular additional contributions, and the compounding effect of investment returns.

Enter your initial investment, monthly contribution, annual rate of return, and investment duration. The results show your total contributions versus the total growth, making the power of investing clearly visible.

Common rates of return: Savings accounts typically yield 2–5%, bonds 3–6%, and diversified stock market index funds historically average around 7–10% annually before inflation. Always consider your risk tolerance when choosing an investment strategy.

Inflation Calculator

Purchasing Power
See how inflation erodes money value
Formula
Future Value = Amount × (1 + rate)ⁿ
Purchasing Power = Amount / (1 + rate)ⁿ
Equivalent Future Value
$18,061
needed in 20 years
Purchasing Power Lost$4,460
Real Value Today's $$5,537
Cumulative Inflation80.6%

Understanding Inflation and Purchasing Power

The inflation calculator shows how the purchasing power of money changes over time due to inflation. It helps you understand what a historical amount of money is worth in today's terms, or what today's money will be worth in the future.

Inflation erodes the value of money over time. For example, $100 in 1990 had far greater purchasing power than $100 today. This calculator uses a specified inflation rate to adjust values forward or backward in time.

Why it matters: If your savings earn less than the inflation rate, you are effectively losing purchasing power each year. This is why investing — not just saving — is important for maintaining real-world wealth over the long term.

Finance Calculator

TVM Calculator
Present & Future Value of money
Time Value of Money
FV = PV(1+r)ⁿ + PMT×[(1+r)ⁿ−1]/r
NPV = Σ CFt / (1+r)^t
Future Value
$17,908
after 10 years
Present Value$10,000
Interest Earned$7,908
Effective Annual Rate6.17%
Doubling Time12.0 yrs

General Finance Calculator

The finance calculator is a flexible tool for solving a variety of time-value-of-money problems. You can calculate any one of five variables — present value, future value, payment amount, interest rate, or number of periods — when you know the other four.

This tool is commonly used for financial planning, loan analysis, and investment comparisons. It mirrors the functionality of a financial calculator used by accountants and financial advisors.

Time value of money is the concept that a dollar today is worth more than a dollar in the future, because money can be invested to earn returns. All financial calculations — from mortgages to retirement planning — are based on this principle.

Income Tax Calculator

US Federal Income Tax
Estimate based on 2025 tax brackets
Estimated Tax
$13,687
federal income tax + FICA
Gross Income$75,000
Taxable Income$59,250
Effective Rate18.25%
Marginal Rate22%
Take-home Pay$61,314
Includes federal income tax + FICA (7.65%). State taxes not included.

How to Use the Income Tax Calculator

The income tax calculator provides an estimate of your income tax liability based on your gross income, filing status, and applicable deductions. It helps you understand how much of your income goes to taxes and plan your finances accordingly.

Enter your annual income, select your filing status, and input any deductions. The calculator applies progressive tax brackets to give you an estimated tax amount, effective tax rate, and after-tax income.

Disclaimer: This calculator provides estimates for general educational purposes. Actual tax liability depends on many factors including credits, exemptions, local taxes, and current tax law. Always consult a qualified tax professional for advice specific to your situation.

Salary Calculator

Salary Breakdown
Convert salary to any pay period
Salary Breakdown
$60,000
per year
Monthly$5,000
Bi-Weekly$2,308
Weekly$1,154
Daily$231
Hourly$28.85

Salary Calculator — Hourly to Annual and More

The salary calculator converts between hourly, weekly, bi-weekly, monthly, and annual pay rates, making it easy to compare job offers expressed in different formats or to understand your total annual compensation.

Enter your pay rate and select how it is expressed (hourly, daily, weekly, etc.). The calculator instantly converts it to all other time periods, assuming a standard 40-hour work week and 52 weeks per year.

Useful for: Comparing a full-time salaried position to a part-time hourly role, calculating the real value of a raise, or converting a freelance rate into an equivalent annual salary for budgeting purposes.

Interest Rate Calculator

Find the Rate
Calculate APR from loan details
Note
Rate is solved iteratively using Newton-Raphson method. Enter known loan details to find the implied interest rate.
Annual Interest Rate
9.56%
APR (Annual Percentage Rate)
Monthly Rate0.797%
Total Payment$13,200
Total Interest$3,200
Cost per $1,000$320

Interest Rate Calculator

The interest rate calculator lets you find the interest rate of a loan or investment when you know the other variables — principal, payments or final value, and time period. It is the reverse of a standard loan or savings calculator.

This is useful when a lender quotes a monthly payment amount without clearly stating the APR, or when you want to determine the effective return rate of an investment. Enter the known values and the calculator solves for the interest rate.

Understanding the actual interest rate helps you compare financial products accurately. A loan with a lower monthly payment is not always cheaper — a longer term can hide a higher effective cost.

Sales Tax Calculator

Sales Tax
Add or reverse sales tax on any amount
Total After Tax
$108.50
total price
Pre-tax Amount$100.00
Tax Amount$8.50
Tax Rate8.5%

Sales Tax Calculator

The sales tax calculator quickly works out the tax amount and total price for any purchase. You can either calculate the tax to add to a pre-tax price, or reverse-calculate the original price from a tax-inclusive total.

Simply enter the price, the sales tax rate (as a percentage), and whether you are adding tax to a base price or extracting tax from a total. The calculator handles both directions instantly.

Sales tax rates vary by country, state, and city. This calculator is a general-purpose tool — always check your local applicable rate. Businesses use tools like this to quickly verify pricing and receipts.

BMI Calculator

Formula
BMI = weight(kg) / height(m)²
Imperial: BMI = 703 × weight(lb) / height(in)²
Your BMI
22.9
Normal weight
Underweight< 18.5
Normal18.5 – 24.9
Overweight25 – 29.9
Obese≥ 30

What Is BMI and How Is It Calculated?

Body Mass Index (BMI) is a simple numerical measure of a person's weight in relation to their height. It is widely used by healthcare professionals as a quick screening tool to categorise individuals as underweight, normal weight, overweight, or obese.

BMI is calculated by dividing your weight in kilograms by the square of your height in metres (kg/m²). Enter your height and weight and choose your preferred unit system (metric or imperial). The result is displayed alongside the standard WHO BMI categories.

Limitations: BMI does not distinguish between muscle and fat, so very muscular individuals may have a high BMI without excess body fat. It should be used alongside other health indicators, not as the sole measure of health. Always consult a healthcare professional for a full assessment.

Calorie Calculator (TDEE)

Daily Calorie Needs (TDEE)
2,545
calories/day to maintain weight
Lose 0.5 kg/week2,045 kcal
Lose 1 kg/week1,545 kcal
Gain 0.5 kg/week3,045 kcal
BMR (base)1,642 kcal

Calorie Calculator — Daily Needs Estimator

The calorie calculator estimates how many calories you need to consume each day to maintain, lose, or gain weight. It is based on your age, sex, height, weight, and physical activity level using established energy expenditure formulas.

The calculation uses your Basal Metabolic Rate (BMR) — the number of calories your body needs at complete rest — multiplied by an activity factor to estimate Total Daily Energy Expenditure (TDEE). From there, you can adjust up or down to reach your goal.

For weight loss: A deficit of 500 calories per day typically results in approximately 0.5 kg (1 lb) of weight loss per week. For muscle gain, a moderate calorie surplus combined with resistance training is recommended. Always prioritise nutritional quality, not just calorie quantity.

Body Fat Calculator

U.S. Navy Method
Uses neck, waist, and hip measurements
Formula (U.S. Navy)
Male: 495/(1.0324−0.19077×log10(waist−neck)+0.15456×log10(height))−450
Female: 495/(1.29579−0.35004×log10(waist+hip−neck)+0.22100×log10(height))−450
Body Fat
18.5%
Fitness
Fat Mass
Lean Mass
Enter weight (kg) below to see fat/lean mass

Body Fat Percentage Calculator

The body fat calculator estimates the percentage of your total body weight that consists of fat, using the US Navy circumference method. Unlike BMI, body fat percentage directly measures fat composition, making it a more informative health indicator.

For men, enter your height, waist, and neck circumference. For women, also enter your hip circumference. All measurements should be taken at consistent points. The calculator applies the validated Navy formula to estimate body fat percentage.

Healthy ranges: For men, 10–20% is considered fit; for women, 18–28%. Athletes typically have lower percentages. Body fat above 25% (men) or 32% (women) is generally considered obese. These are general guidelines — individual health assessments may vary.

BMR Calculator

Basal Metabolic Rate
Calories burned at complete rest
Mifflin-St Jeor Formula
Male: (10×W) + (6.25×H) − (5×A) + 5
Female: (10×W) + (6.25×H) − (5×A) − 161
BMR
1,695
calories/day at rest
Sedentary (×1.2)2,034
Light Activity (×1.375)2,331
Moderate (×1.55)2,627
Very Active (×1.725)2,924
Extra Active (×1.9)3,221

BMR Calculator — Basal Metabolic Rate

Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest just to maintain basic functions — breathing, circulation, cell repair, and temperature regulation. It represents the minimum energy your body needs to survive.

This calculator uses the Mifflin-St Jeor equation, the most widely validated BMR formula in use today. Enter your age, sex, height, and weight to get your BMR, along with calorie estimates for five different activity levels.

Your BMR is the foundation of all calorie and nutrition calculations. Multiplied by an activity factor, it gives you your Total Daily Energy Expenditure (TDEE) — the total calories you burn per day. This number tells you exactly how much to eat to maintain, lose, or gain weight.

Ideal Weight Calculator

Multiple formulas compared
Robinson, Miller, Devine & Hamwi methods
Ideal Weight Range
70–75 kg
recommended range
Robinson (1983)
Miller (1983)
Devine (1974)
Hamwi (1964)

Ideal Body Weight Calculator

The ideal weight calculator provides a healthy target weight range for your height based on four widely used medical formulas: Robinson (1983), Miller (1983), Devine (1974), and Hamwi (1964). Each formula gives a slightly different result, so the tool presents a range rather than a single number.

Enter your height in centimetres and optionally your current weight to see how you compare. The calculator displays the range across all four formulas, giving you a realistic healthy weight window rather than a single rigid target.

Important: Ideal weight formulas are general guidelines based on population averages. They do not account for muscle mass, bone density, ethnicity, or body composition. Use this as one data point among many — consult a healthcare provider for personalised advice.

Pace Calculator

Your Pace
6:00
min/km
Finish Time1:00:00
Speed10.0 km/h
5K time30:00
10K time1:00:00
Half Marathon2:11:10
Marathon4:22:21

Running Pace Calculator

The pace calculator is a versatile running tool that can solve for pace, finish time, or distance — depending on which two values you already know. It is essential for runners preparing for a 5K, 10K, half marathon, or full marathon.

Switch between three modes: Pace (calculate pace from distance and time), Time (calculate finish time from pace and distance), or Distance (calculate distance from pace and time). The tool also shows your equivalent speed and projected times for standard race distances.

Pace is typically expressed as minutes per kilometre (min/km) or minutes per mile (min/mi). A pace of 5:00/km means you run 1 kilometre every 5 minutes, equivalent to a 12 km/h speed. This tool supports both km and mile units.

Pregnancy Calculator

Track your pregnancy
Week-by-week milestones from LMP
How it works
Gestational age counts from LMP.
Due date = LMP + 280 days (Naegele's rule).
Current Week
weeks pregnant
Due Date
Days Until Due
Trimester
1st Trimester Ends
2nd Trimester Ends

Pregnancy Calculator — Due Date and Weeks

The pregnancy calculator estimates your due date, current gestational age, and trimester based on your last menstrual period (LMP). Pregnancy is counted from the first day of the LMP, making a full-term pregnancy approximately 40 weeks (280 days).

Enter your last menstrual period date and the calculator will show your estimated due date, how many weeks and days pregnant you are, which trimester you are in, and the key trimester milestone dates.

Note: Due dates are estimates — only about 5% of babies are born on their exact due date. Actual delivery typically occurs within 2 weeks before or after the calculated date. Always confirm dates and receive proper prenatal care from a qualified healthcare provider.

Pregnancy Conception Calculator

Fertile Window & Ovulation
Find your best conception days
Ovulation Date
estimated ovulation
Fertile Window Start
Fertile Window End
Next Period (est.)
Days Until Ovulation

Conception and Ovulation Calculator

The conception calculator estimates your ovulation date and fertile window based on your last menstrual period and average cycle length. Understanding when ovulation occurs is the foundation of both natural family planning and conception efforts.

Enter your last menstrual period date and your average cycle length (typically 28 days, but can range from 21–35 days). The calculator identifies your estimated ovulation day and the fertile window — the days when conception is most likely.

The fertile window is generally the 5 days before ovulation plus the day of ovulation itself, as sperm can survive up to 5 days in the reproductive tract. These calculations are estimates based on a regular cycle — actual ovulation can vary.

Due Date Calculator

Naegele's Rule
Due Date = LMP + 280 days
(40 weeks from LMP, 38 weeks from conception)
Due Date
estimated delivery date
Days Remaining
Current Week
Trimester
Earliest Full-term
Latest (42 weeks)

Due Date Calculator — Three Methods

The due date calculator estimates the expected delivery date using three different methods: Last Menstrual Period (LMP), conception date, or IVF transfer date. Each method is suited to different situations depending on what information you have.

The LMP method adds 280 days to your last period. The conception method adds 266 days to the known conception date. The IVF method accounts for embryo age (Day 3 or Day 5 transfer). All methods show the due date, current gestational week, trimester, and delivery range.

A full-term pregnancy is considered 37–42 weeks. The due date shown is the estimated 40-week mark. Premature birth (before 37 weeks) and post-term pregnancy (after 42 weeks) are both managed medically. Regular prenatal appointments are the best way to monitor fetal development.

Fraction Calculator

+
=
5
6
Decimal0.8333
Mixed Number

Fraction Calculator — Add, Subtract, Multiply, Divide

The fraction calculator performs arithmetic operations on fractions: addition, subtraction, multiplication, and division. It also includes a simplification mode that reduces any fraction to its lowest terms and converts it to a decimal and mixed number.

Enter the numerator and denominator of each fraction and select the operation. Results are automatically simplified by dividing by the greatest common divisor (GCD). The calculator also shows the decimal equivalent and mixed number form.

Fractions are fundamental in mathematics, cooking, construction, and finance. Understanding how to add fractions with different denominators (finding a common denominator) is a core arithmetic skill tested in school and used throughout daily life.

Random Number Generator

True Random Numbers
Cryptographically strong generation
Result
click Generate
Range1 – 100
Total Possible100

Random Number Generator

The random number generator produces truly random integers within any range you specify. It can generate a single number or multiple numbers at once, with the option to exclude duplicates from the results.

Set your minimum and maximum values, choose how many numbers to generate, and select whether duplicates are allowed. The generator uses JavaScript's cryptographically seeded Math.random() for unbiased results suitable for games, decisions, and sampling.

Common uses: Picking lottery numbers, selecting a random winner from a list, generating random test data, rolling virtual dice (1–6), simulating a coin flip (0–1), assigning random groups for a classroom activity, or making any other random selection.

Triangle Calculator

Enter all three sides
Area
square units
Perimeter
Angle A
Angle B
Angle C
Side a
Side b
Side c
Type

Triangle Calculator — All Sides and Angles

The triangle calculator solves any triangle given sufficient information about its sides and angles. It supports four input modes: SSS (three sides), SAS (two sides and the included angle), ASA (two angles and the included side), and right triangle (two sides of a right triangle).

The calculator uses the Law of Cosines for SSS and SAS cases, and the Law of Sines for ASA cases. Results include all three sides, all three angles, the area, perimeter, and triangle type (acute/obtuse/right, equilateral/isosceles/scalene).

Triangle calculations are fundamental in geometry, construction, engineering, navigation, and surveying. Knowing any three elements of a triangle (where at least one is a side) is sufficient to determine the entire triangle.

Standard Deviation Calculator

Enter your data set
Separate numbers with commas or spaces
Formula
σ = √(Σ(xᵢ−μ)² / N) — Population
s = √(Σ(xᵢ−x̄)² / (N−1)) — Sample
Std Deviation
sample std dev
Mean (avg)
Median
Mode
Variance
Range
Min / Max
Count (N)
Sum

Standard Deviation Calculator

The standard deviation calculator computes key statistical measures for a set of numbers: mean, median, mode, variance, standard deviation, range, and count. Enter your data as a comma or space-separated list.

Choose between population standard deviation (σ) when your data represents an entire population, or sample standard deviation (s) when your data is a sample from a larger group. The sample formula divides by (n−1) rather than n to account for sampling bias.

What standard deviation tells you: A low standard deviation means the values are clustered close to the mean. A high standard deviation indicates the values are spread out widely. It is a fundamental measure of variability used in statistics, finance, science, and quality control.

Percentage Calculator

WHAT IS X% OF Y?
% of = 30
X IS WHAT % OF Y?
is what % of = 15%
% CHANGE FROM X TO Y
= +25%

Percentage Calculator — Three Ways to Calculate

The percentage calculator solves three common percentage problems: finding what percent one number is of another, calculating a percentage of a number, and working out the percentage change (increase or decrease) between two values.

These three modes cover the vast majority of everyday percentage calculations — from calculating a tip at a restaurant and understanding a sale discount, to tracking growth rates in business and computing grade scores in education.

Example uses: "What is 15% of 80?" → 12. "30 is what percent of 120?" → 25%. "A price went from $50 to $65 — what is the percentage increase?" → 30%. All three types are instantly solved with this tool.

Scientific Calculator

0

Scientific Calculator — Advanced Math Operations

The scientific calculator performs advanced mathematical operations beyond basic arithmetic, including trigonometry (sin, cos, tan), logarithms, exponents, square roots, powers, parentheses, and the constant π. It is designed for students, engineers, and scientists.

Trigonometric functions use JavaScript's standard radian-based math functions. Parentheses can be used to control calculation order, and the display shows the current expression while you build it.

All standard order-of-operations rules apply. Parentheses can be used to control calculation order. This tool is suitable for high school and university-level mathematics, physics, and engineering coursework.

Age Calculator

Leave blank for today
Your Age
35
years old
Months428
Weeks1,863
Days13,047
Next Birthdayin 33 days

Age Calculator — Exact Age in Years, Months, and Days

The age calculator computes the exact age between two dates — typically a date of birth and today's date. It returns the result in years, months, and days, giving you a precise age rather than just a rounded year count.

Enter a date of birth and optionally a target date (default is today). The calculator counts across leap years and varying month lengths to give an accurate result. It also shows the total age expressed in months, weeks, and days.

This tool is useful for calculating age for official forms, understanding eligibility requirements (where age must exceed a threshold on a specific date), planning milestone birthdays and anniversaries, or any situation where exact age matters.

Date Difference Calculator

Leave blank for today
Difference
498
days
Years1
Months16
Weeks71
Business Days356

Date Difference Calculator

The date difference calculator calculates the number of days, weeks, months, and years between any two dates. It is useful for counting down to events, measuring elapsed time, calculating deadlines, or determining contract durations.

Enter a start date and end date. The calculator returns the difference expressed in multiple units: total days, weeks and days, and an approximate breakdown in months and years. Negative values appear if the start date is after the end date.

Common uses: How many days until a holiday or exam? How long has it been since a specific event? How many days are between two contract dates? This calculator handles all these questions instantly, accounting for leap years and varying month lengths.

Length Converter

Length Converter — All Units Instantly

The length converter converts between all common units of length and distance: metres, kilometres, centimetres, millimetres, miles, yards, feet, inches, and nautical miles. Enter a value in any unit and all other units update instantly.

This tool is useful for international travel, engineering, construction, and science — any situation where you need to convert between metric and imperial measurement systems. All conversion factors are precise and based on the official SI unit definitions.

Key conversions: 1 inch = 2.54 cm; 1 foot = 30.48 cm; 1 mile = 1.609 km; 1 nautical mile = 1.852 km. The metre is the base unit of length in the International System of Units (SI).

Temperature Converter

Formulas
°F = °C × 9/5 + 32
K = °C + 273.15
°C = (°F − 32) × 5/9

Temperature Converter — Celsius, Fahrenheit, Kelvin

The temperature converter instantly converts between Celsius (°C), Fahrenheit (°F), and Kelvin (K) — the three most commonly used temperature scales in everyday life and science.

Celsius is the standard scale used in most countries and scientific contexts. Fahrenheit is used primarily in the United States. Kelvin is the SI unit used in physics and chemistry, where 0 K represents absolute zero — the coldest possible temperature.

Quick reference: Water freezes at 0°C / 32°F / 273.15 K and boils at 100°C / 212°F / 373.15 K. Normal human body temperature is approximately 37°C / 98.6°F. Enter any temperature in any scale to see all three values at once.

Time Calculator

Add or Subtract Time
Calculate time differences and sums
Total Time
05:06:15
hours : minutes : seconds
Total Hours5.1
Total Minutes306
Total Seconds18,375

Time Calculator — Add and Subtract Time

The time calculator lets you add or subtract two time values expressed in hours, minutes, and seconds. This is useful for scheduling, work time tracking, calculating durations, and any situation where you need to perform arithmetic on time values.

Enter two time values in HH:MM:SS format and choose whether to add or subtract them. The result is shown in hours:minutes:seconds format, as well as converted to total hours, minutes, and seconds for easy reference.

Example: If a task starts at 09:30:00 and ends at 14:15:30, subtracting gives a duration of 4 hours 45 minutes 30 seconds. This tool handles time values exceeding 24 hours without wrapping around the clock, making it ideal for total duration calculations.

Hours Calculator

Work Hours Tracker
Calculate hours worked and pay
StartEnd
8h
8h
Total Hours Worked
16.0
hours (net of breaks)
Gross Hours17.0
Break Time1.0 hrs
Days Worked2
Avg per Day8.0 hrs
Estimated Pay$400.00

Hours Calculator — Work Time Tracker

The hours calculator adds up your work hours across multiple shifts or days. Enter start and end times for each period and the calculator totals your hours, subtracts break time, and optionally calculates your earnings based on an hourly rate.

This tool is ideal for freelancers, hourly workers, managers, and anyone who needs to track time for payroll, billing, or project management purposes. Add as many rows as you need for different days or shifts.

How to use it: Enter start and end times for each shift. Add a standard break duration in minutes. Optionally enter your hourly rate to see total pay. The summary shows gross hours, net hours after breaks, average hours per day, and total earnings.

GPA Calculator

Calculate Your GPA
Enter grades and credit hours per course
CourseGradeCredits
Your GPA
3.10
on a 4.0 scale
Letter GradeB
Total Credits10
Grade Points31.0
StandingGood Standing
GPA Scale
A=4.0 · A-=3.7 · B+=3.3 · B=3.0
B-=2.7 · C+=2.3 · C=2.0 · D=1.0 · F=0

GPA Calculator — Weighted Grade Point Average

The GPA calculator computes your Grade Point Average from individual course grades and credit hours. It uses the standard 4.0 scale used by most universities and colleges in the United States and internationally.

Enter each course name, select the letter grade (A through F), and enter the credit hours for that course. The calculator uses weighted averaging — courses with more credit hours have a proportionally greater impact on your overall GPA.

GPA scale: A = 4.0, A− = 3.7, B+ = 3.3, B = 3.0, B− = 2.7, C+ = 2.3, C = 2.0, and so on. A GPA of 3.5 or above typically qualifies for the Dean's List. A GPA below 2.0 may result in academic probation at many institutions.

Grade Calculator

Weighted Grade Calculator
Enter scores and weights for each category
AssignmentScore (%)Weight (%)
Overall Grade
88.0%
Letter Grade: B+
Total Weight Used100%
Weighted Score88.0
GPA Equivalent3.3
Grade Scale
A: 90-100 · B: 80-89 · C: 70-79
D: 60-69 · F: below 60

Grade Calculator — Weighted Course Average

The grade calculator computes your overall course grade from individual assignments, tests, and projects using weighted averaging. Each assignment has a score (percentage) and a weight (how much it counts toward your final grade).

Enter each assignment or assessment, its percentage score, and its weight. Weights do not need to add up to 100 — the calculator normalises them automatically. The result shows your overall percentage, letter grade, and GPA equivalent.

Example: If homework counts 20%, midterm 30%, and final exam 50% — enter each with those weights and your scores. The weighted average reflects the relative importance of each component, giving you a more accurate picture of your standing than a simple average.

Concrete Calculator

Estimate Concrete Volume
Calculate bags and cost for your project
Concrete Needed
0.31
cubic yards
Cubic Feet8.3
Bags Needed14
Bags + 10% waste16
Estimated Cost$88.00

Concrete Calculator — Volume Estimator

The concrete calculator estimates the volume of concrete needed for a construction project — whether it's a flat slab, a rectangular footing, or a cylindrical column. It supports three common concrete forms and returns results in cubic feet and cubic yards.

Select your pour type (slab, footing, or column), enter the dimensions, and the calculator gives you the volume in cubic feet, cubic yards, and the approximate number of 60 lb and 80 lb pre-mixed bags needed. A 10% waste buffer is recommended for all pours.

Ready-mix vs bags: For small projects (patios, pathways), pre-mixed bags are cost-effective. For volumes above 1 cubic yard (27 cubic feet), ready-mix concrete delivered by truck is usually more economical and ensures a consistent mix quality.

Subnet Calculator

IPv4 Subnet Calculator
Calculate network addresses, ranges, and more
Network Address
192.168.1.0
network / CIDR
Subnet Mask255.255.255.0
Broadcast192.168.1.255
First Host192.168.1.1
Last Host192.168.1.254
Usable Hosts254
Total Addresses256

Subnet Calculator — IP Network Planning

The subnet calculator computes key networking parameters from an IP address and CIDR prefix or subnet mask, including the network address, broadcast address, usable host range, and total number of usable hosts.

Enter an IPv4 address and a CIDR notation (e.g. /24) or subnet mask (e.g. 255.255.255.0). The calculator returns the network address, broadcast address, first and last usable host addresses, and the number of hosts the subnet can accommodate.

Common subnets: /24 = 254 usable hosts (class C), /16 = 65,534 hosts, /8 = 16 million hosts. Subnetting is fundamental to network design, IP address management, and security — allowing administrators to divide large networks into smaller, manageable segments.

Password Generator

Generate Strong Passwords
Cryptographically secure random passwords
Generated Passwords
Length16
StrengthVery Strong
Entropy95 bits
Character Pool91

Password Generator — Strong and Secure

The password generator creates cryptographically random, strong passwords of any length. You can customise the character set to include uppercase letters, lowercase letters, numbers, and special symbols depending on the site's requirements.

Strong passwords are the first line of defence against unauthorised account access. A good password should be at least 12 characters long, use a mix of character types, and be unique for every account. This generator creates passwords that are practically impossible to guess or brute-force.

Best practices: Use a different password for every account. Consider using a reputable password manager (such as Bitwarden or 1Password) to store them securely. Enable two-factor authentication (2FA) wherever available for an additional layer of security.

Conversion Calculator

1 meter
3.281
feet

Unit Conversion Calculator — All Categories

The conversion calculator covers a wide range of measurement categories including length, weight, volume, area, speed, data storage, energy, and pressure. Select a category, enter a value in any unit, and instantly see the equivalent in all other units.

All conversion factors used are based on official SI (International System of Units) definitions and internationally recognised standards. The calculator is suitable for everyday use, academic work, engineering, cooking, fitness, and international travel.

Categories available: Length (metre to inch), Weight (kilogram to pound), Volume (litre to gallon), Area (square metre to acre), Speed (km/h to mph), Data (bytes to gigabytes), Energy (joule to calorie), and Pressure (pascal to PSI). More categories are added regularly.