Free Unit Converter — Length, Weight, Temperature & More
Convert between metric and imperial units instantly. Pick a category, type a value, done.
Frequently Asked Questions
How many centimeters are in an inch?
Exactly 2.54 cm per inch — the definition was fixed internationally in 1959. That makes a foot 30.48 cm and a yard 0.9144 m exactly.
Are these conversions exact?
Length, weight, volume, and area conversions use the exact legal definitions. Results display up to 8 significant digits; tiny rounding in the last digit is normal for repeating decimals.
Does the volume category use US or UK measures?
US customary: a US gallon is 3.785 liters, a US fluid ounce 29.574 ml. UK (imperial) pints and gallons are about 20% larger — worth checking when following British recipes.
How does temperature conversion work?
°F = °C × 9/5 + 32, and Kelvin is Celsius + 273.15. Temperature is the one category where units don't scale proportionally, so the converter handles those formulas specially.