Unit Converters

Length, weight, volume, temperature, and cooking measurements.

3 tools · all run in your browser

Convert between metric, imperial, and US customary units for length, mass, volume, area, time, digital storage, speed, temperature, and cooking. Every conversion runs on your device using standard SI-defined factors — no rounding surprises, no server round-trip.

Two things that trip most people up: temperature isn't just a multiplication (Celsius to Fahrenheit uses an offset), and digital storage has both decimal (KB, MB, GB — used by disk manufacturers) and binary (KiB, MiB, GiB — used by RAM and operating systems) forms that differ by ~2.4% per prefix. Our tools show both when it matters.

For everyday cooking conversions like cups to millilitres or tablespoons to grams, use the dedicated Cooking Converter — it uses US customary measurements which differ from UK and Australian equivalents.

All unit converters

Frequently asked

What is the difference between KB and KiB?

KB is 1,000 bytes (decimal, used by disk manufacturers and networking). KiB is 1,024 bytes (binary, used by RAM and operating systems). A "500 GB" drive shows as ~465 GiB in Windows because Windows uses the binary form — same bytes, different unit.

How do I convert Celsius to Fahrenheit?

The formula is (°C × 9/5) + 32 = °F. Because it uses an offset (+32), you can't just multiply by a factor like you can for length or mass. Our Universal Converter handles this automatically.

How many millilitres in a US cup?

A US customary cup is 236.588 mL. A US legal cup (used on nutrition labels) is 240 mL. A UK metric cup is 250 mL. Always check which system your recipe uses.

What is the metric equivalent of a US tablespoon?

A US tablespoon is 14.787 mL. A metric tablespoon (used in most of the world outside the US) is 15 mL. A UK tablespoon is 17.758 mL — a real trap for baking.

Which units should I use for scientific work?

Always SI: metres (length), kilograms (mass), seconds (time), Kelvin (temperature), litres (volume). Most scientific journals require SI even when the underlying measurement was in imperial.