Everyday Life

Unit Converter

Convert length, weight, temperature, volume, area, speed and data units instantly.

How it works

Pick a category, choose the unit you are converting from and the unit you want, and the result appears as you type. There is nothing to submit.

Most conversions work through a base unit. Every length is defined relative to the metre, every mass relative to the kilogram, and so on. Converting inches to miles means converting inches to metres, then metres to miles - which keeps every pair in a category consistent with every other.

Temperature is handled separately because the scales have different zero points as well as different sizes. Celsius, Fahrenheit and Kelvin need an offset applied, not just a multiplier, so they use their own conversion path.

Data units include both decimal and binary sizes. A kilobyte here is 1,000 bytes, matching the SI definition used on storage packaging, while a kibibyte is 1,024 bytes, matching what most operating systems report.

Formula

Standard conversion

result = value × (factor of from-unit) ÷ (factor of to-unit)

Factors are defined against the category base unit.

Celsius to Fahrenheit

°F = (°C × 9 ÷ 5) + 32

Fahrenheit to Celsius

°C = (°F − 32) × 5 ÷ 9

Celsius to Kelvin

K = °C + 273.15

Worked examples

1 kilometre = 0.621371 miles

A kilometre is 1,000 metres and a mile is 1,609.344 metres.

100 °C = 212 °F = 373.15 K

The boiling point of water at sea level, shown on all three temperature scales.

1 GB = 1,000 MB, but 1 GiB = 1,024 MiB

This is why a drive sold as 1 TB shows as roughly 931 GiB in your operating system.

Frequently asked questions

Why is a kilobyte 1,000 bytes and not 1,024?

Because KB is the SI decimal unit, which is what storage manufacturers use. The binary unit is the kibibyte (KiB), which is 1,024 bytes. Both are available here so you can convert either way and see the difference.

Which gallon does the volume converter use?

The US liquid gallon of 3.785411784 litres, along with US quarts, pints and cups. The imperial gallon used in the UK is larger at 4.54609 litres, so do not mix the two.

How precise are the results?

Conversions use exact definitions where they exist - an inch is exactly 2.54 cm, a mile is exactly 1,609.344 m. Results are displayed to a sensible number of significant figures, with the full precision kept internally.

Can I convert negative values?

Yes, where it makes sense. Negative temperatures are valid and convert correctly. Negative lengths, masses and data sizes are accepted arithmetically but are rarely meaningful.