How to use the unit converter
- Choose a category such as Length or Digital storage.
- Enter the value and pick the unit it is in and the unit you want.
- Read the result, the multiplication that produced it and the reverse factor. Tap the swap button to convert the other way.
- Scroll the table to see the same value in every unit of the category, with a copy button on each row.
Features
- Eight categories: length, weight/mass, temperature, digital storage, time, area, volume and speed
- Exact international factors: 1 in = 2.54 cm, 1 lb = 0.45359237 kg, 1 mi = 1,609.344 m
- Temperature conversions by formula (Celsius, Fahrenheit, Kelvin)
- Decimal (KB, MB, GB, TB) and binary (KiB, MiB, GiB, TiB) storage units, bits and bytes
- Conversion factor and formula shown, plus a full comparison table
How the conversions work
Every unit in a category is defined as an exact multiple of a base unit (metres, kilograms, bits, seconds, square metres, litres, metres per second). A conversion multiplies by the source factor and divides by the target factor: 170 cm to inches is 170 × 0.01 ÷ 0.0254 = 66.93 in. The factors come from the international definitions of the yard and pound agreed in 1959 and the SI.
Temperature is different because the scales have different zero points, so formulas are used instead: °F = °C × 9 ÷ 5 + 32, K = °C + 273.15. A temperature difference and a temperature reading are not the same thing; a 10 °C rise is an 18 °F rise, not 50 °F.
Megabytes versus mebibytes
Drive makers, network speeds and the SI use decimal prefixes: 1 GB = 1,000,000,000 bytes. Operating systems and memory sizes traditionally use binary steps of 1,024: 1 GiB = 1,073,741,824 bytes, which Windows still labels “GB”. That is why a 500 GB drive shows as about 465 GB in Windows. This converter keeps the two families separate so you can convert exactly. Bits are one eighth of a byte; internet speeds are quoted in megabits per second.
Assumptions and limits
US customary volumes (cups, pints, gallons, fluid ounces) are used; the UK gallon is listed separately and UK pints or cups are not included. A month is taken as the Gregorian average of 30.44 days and a year as 365.2425 days. Results are rounded for display; copy them for full precision as shown.