Unit converters

Eight converters covering the units people actually look up. Every conversion passes through a stated base unit using exact, internationally standardized factors — no hidden rounding.

• Length ConverterConvert between metric and imperial/US customary length units. All conversions pass through the metre, using the exact 1959 international yard-and-pound definitions (1 inch = 25.4 mm exactly).
• Weight ConverterConvert between metric and imperial/US weight (mass) units. All conversions pass through the kilogram, using exact avoirdupois definitions (1 pound = 0.45359237 kg exactly).
• Temperature ConverterConvert between Celsius, Fahrenheit, and Kelvin. Temperature conversions are affine (they involve an offset as well as a scale), so this converter applies the exact defining formulas rather than a simple multiplier.
• Area ConverterConvert between metric and imperial/US area units, derived from the exact length definitions (so 1 square foot = 0.09290304 m² exactly).
• Volume ConverterConvert between metric and US customary volume units. All conversions pass through the litre; US customary units are used (1 US gallon = 3.785411784 L exactly).
• Speed ConverterConvert between common speed units. All conversions pass through metres per second, derived from the exact length and time definitions.
• Data Size ConverterConvert between digital storage units. Both decimal (SI, powers of 1000: KB, MB, GB) and binary (IEC, powers of 1024: KiB, MiB, GiB) units are included — the difference matters at large sizes.
• Energy ConverterConvert between energy units including joules, calories, kilowatt-hours, and BTU, using internationally standardized definitions.