Conversion
Unit converters for length, weight, volume, temperature and more.
Converters for the units that come up in cooking, travel, engineering and schoolwork — length, weight, volume, temperature, pressure, energy, data and more.
Each one uses the formally defined factor rather than a rounded approximation, so the result is as exact as the definition allows.
15 calculators in this category
Unit Converter
Convert between length, weight, temperature, volume, and more.
Temperature Converter
Convert between Celsius, Fahrenheit, and Kelvin instantly.
Length Converter
Convert between meters, feet, inches, miles, kilometers, and more.
Speed Converter
Convert between mph, km/h, m/s, knots, and more.
Number Base Converter
Convert numbers between binary, octal, decimal, and hexadecimal.
Weight Converter
Convert between kg, lbs, oz, stone, tons, and more.
Volume Converter
Convert between liters, gallons, cups, cubic meters, and more.
Area Converter
Convert between square meters, acres, hectares, and more.
Pressure Converter
Convert between Pa, bar, PSI, atm, torr, and more.
Energy Converter
Convert between joules, calories, kWh, BTU, and more.
Power Converter
Convert between watts, kilowatts, horsepower, BTU/hr.
Data Storage Converter
Convert between bits, bytes, KB, MB, GB, TB, and more.
Cooking Converter
Convert cups, tablespoons, ounces, grams, and temperatures.
Fuel Efficiency Converter
Convert between MPG, L/100km, and km/L.
Angle Converter
Convert between degrees, radians, gradians, arcminutes.
Which calculator do I need?
Start from the job rather than the tool.
- Convert almost anything — Unit ConverterStart here if you are not sure which converter you need.
- Switch between metric and imperial distance — Length Converter
- Convert a weight for a recipe or a parcel — Weight Converter or Cooking Converter
- Convert cups, litres and fluid ounces — Volume Converter or Cooking Converter
- Convert a temperature — Temperature Converter
- Convert a speed or a pace — Speed Converter
- Work out land or floor area in other units — Area Converter
- Convert tyre, gas or blood pressure units — Pressure Converter
- Convert energy or power figures — Energy Converter or Power Converter
- Convert file sizes and transfer rates — Data Storage Converter
- Compare fuel economy across countries — Fuel Efficiency Converter
- Convert between binary, hex and decimal — Number Base Converter
What these calculators have in common
Assumptions worth knowing before you rely on any result here.
Some factors are exact, others are measured
An inch is exactly 2.54 cm by international agreement, so that conversion is precise. Older and regional units were defined against physical standards, so their metric equivalents are rounded. Where a result has many decimal places, that is the definition showing through, not false precision.
Same name, different size
A US gallon is 3.785 litres and a UK gallon is 4.546. A US cup is 237 ml against a metric cup at 250, and an Australian tablespoon is 20 ml where most others are 15. Check which variant a recipe or spec means before converting.
Converting there and back can shift the last digit
Each step rounds slightly, so metres to feet and back may not return the exact number you started with. It is a rounding artefact rather than an error, and it is invisible at any practical precision.