Education: math help and study tools
Calculators and guides for coursework: percentages, fractions, averages, ratios, GPA and unit conversion. The guides explain the method so you can do the working by hand on an exam.
Unit conversion
- Length ConverterConvert between millimeters, centimeters, meters, kilometers, inches, feet, yards and miles.
- Weight ConverterConvert kilograms, grams, pounds, ounces, stone and tonnes.
- Temperature ConverterConvert between Celsius, Fahrenheit and Kelvin.
- Area ConverterConvert square meters, square feet, acres, hectares, square miles and more.
- Volume ConverterConvert liters, milliliters, US gallons, imperial gallons, quarts, pints, cups and cubic units.
- Speed ConverterConvert km/h, mph, m/s, knots and feet per second.
- Time ConverterConvert seconds, minutes, hours, days, weeks, months and years.
- Data Storage ConverterConvert bits, bytes, KB, MB, GB, TB and the binary units KiB, MiB, GiB and TiB.
Percentages
- Percentage CalculatorFind X% of a number, what percent one number is of another, or the total behind a percentage.
- Percentage Increase CalculatorFind the percentage increase between two numbers, or raise a number by a percentage.
- Percentage Decrease CalculatorFind the percentage decrease between two numbers, or reduce a number by a percentage.
- Percentage Difference CalculatorCompare two numbers as a percentage when neither one is the starting point.
Math and statistics
Writing and text
School and grades
Guides to go with these tools
All guides- Guide · September 19, 2026How to Add, Subtract, Multiply and Divide Fractions
- Guide · September 19, 2026How to Calculate a Discount and the Sale Price
- Guide · September 19, 2026How to Calculate a Percentage
- Guide · September 19, 2026How to Calculate GPA on a 4.0 Scale
- Guide · September 19, 2026How to Calculate Percentage Decrease
- Guide · September 19, 2026How to Calculate Percentage Increase