About Fast Converters

Fast Converters is a free website for everyday and technical unit conversion. It covers 37 categories, from length, weight and temperature to pressure, energy, data storage and fuel economy, plus calculators and tools that run in your browser.

How the converters work

Every conversion is calculated on your device from published conversion factors (SI definitions and NIST values). Nothing you type into a converter is sent to a server. Exact definitions are used where they exist, for example 1 inch = 2.54 cm exactly.

What we focus on

• Instant, live results with no button to press.
• The formula and a worked example for the most popular conversions, so you can check the maths yourself.
• Clear notes where conventions differ, such as US and UK gallons or decimal and binary data units.

Corrections

If you find a wrong factor, an unclear explanation or a conversion we should add, please contact us. See also our privacy policy.