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MeasureMate

84 calculators and converters

Calculators that show their working

Mortgage payments, unit conversions, grades, calorie needs, date math. Get the answer, then see the formula behind it and a worked example you can check by hand.

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Unit Converters 16 tools Daily Life 19 tools Health & Fitness 11 tools Time & Dates 11 tools Finance 15 tools Education 7 tools Technology 5 tools

Most used

Percentage Calculator Solve the five common percentage questions: X% of Y, X as a percent of Y, increase, decrease, and the whole from a part. Mortgage Calculator Calculate the fixed monthly principal-and-interest payment on a home loan, the total repaid and a month-by-month amortization schedule. BMI Calculator Calculate your Body Mass Index from weight and height in metric or US units, with the WHO category and the healthy weight range for your height. Grade Calculator Work out your current course grade from weighted categories and the score you need on the final exam to reach a target grade. Temperature Converter Convert a temperature between Celsius, Fahrenheit and Kelvin, with a note on how it feels and a check against absolute zero. Compound Interest Calculator Project the growth of a deposit with compound interest and optional monthly contributions, separating what you put in from interest earned. Tip Calculator Calculate the tip and total on a bill and split it evenly, with each share rounded up to the cent so the bill is always covered. Age Calculator Calculate exact age in years, months and days from a date of birth, plus days and weeks lived and the countdown to the next birthday.

New

Tools for students

Work out the score you need on a final, average weighted assignments, simplify fractions, convert to scientific notation or plan study hours before an exam.

Grade Calculator Weighted Average Calculator Fraction Calculator Scientific Notation Converter
All school calculators

More than a number

Run the numbers

Every tool works in the page: type your values and the result updates as you go, in metric or US units where both apply.

See the formula

Below each tool the equation is written out with every symbol defined, so you can check the method, not just the answer.

Follow a worked example

Each page walks through one realistic case step by step, with the same numbers our automated tests check.

Every formula on the site is covered by automated unit tests that run before each release. How we check the math

Guides

All guides
A growing stack of coins with a small plant sprouting from the top

Compound Interest Worked Through: Savings, Starting Early, Fees and Debt

Interest that earns interest, shown with computed examples: how compounding frequency changes a balance, how accurate the Rule of 72 is, why ten early years of saving can beat thirty later ones, and how the same math works against a card balance.

 A world map with clock faces showing different times across multiple cities

Time Zone Differences: Why the Gap Changes and How to Schedule Around It

New York and Berlin are usually six hours apart, but not for three weeks every March. Dated examples show when gaps between cities shift and how to plan meetings and deadlines around them.

 Electrical power lines at sunset with an energy meter in the foreground

Energy Units Explained: Joules, kWh, Calories and BTU With Worked Examples

Every energy unit is a fixed number of joules. Once you know the handful of factors, a food label, a gas bill in therms and an air conditioner rated in BTU per hour all go on the same scale. Worked examples show the steps.