Unit Converters

Metric to imperial and back, with the exact definitions shown and a reference table on every page. Length, weight, temperature, volume, speed, data and shoe sizes.

Length Convertercm to inches, metres to feet, km to miles and back.Weight Converterkg to lbs, stone, grams, ounces and tonnes.Temperature ConverterCelsius, Fahrenheit and Kelvin, with the formulas explained.Volume ConverterLitres, gallons, cups, tablespoons and fluid ounces.Speed Converterkm/h, mph, knots, m/s — plus running pace.Data Storage ConverterKB, MB, GB, TB — and why your drive looks smaller than the box said.Shoe Size ConverterUS, UK and EU shoe sizes, anchored to real foot length.

About the numbers

Every conversion here uses the agreed international factor rather than a rounded one: an inch is exactly 25.4 mm, a pound exactly 0.45359237 kg. Temperature is the odd one out, because it carries an offset as well as a multiplier — which is why −40 is the same reading in Celsius and Fahrenheit. Data storage is shown both in the decimal sizes drive makers print on the box and the binary ones your computer counts in. That gap is why a 1 TB drive shows up as about 931 GB.