Unit Converter
Pick a dimension, type a value, see every common unit at once. Length, weight, temperature, volume, area, speed — metric + imperial, side by side. Conversions run in your browser.
Show all conversions for this value
| Unit | Symbol | Value |
|---|
What's included
- Length — mm, cm, m, km, in, ft, yd, mi, nautical mile
- Weight — mg, g, kg, t, oz, lb, st, US ton
- Temperature — Celsius, Fahrenheit, Kelvin, Rankine
- Volume — ml, l, m³, US tsp/tbsp/cup/pt/qt/gal/fl oz, UK gal
- Area — mm², cm², m², km², in², ft², yd², acre, hectare, mi²
- Speed — m/s, km/h, mph, knots, ft/s
How it works
Each dimension has a canonical SI base unit (meters for length, kilograms for weight, etc.) and a list of conversion factors to that base. To convert from unit A to unit B in the same dimension: multiply by A's factor, divide by B's factor. The base value is just an intermediate.
Temperature is the exception. Fahrenheit, Celsius, Kelvin, and
Rankine each use a different zero-point, so they need affine
transforms (multiply and add). See
sites/unit/src/lib/units.ts in the source.
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FAQ
Is anything I enter sent to a server?
No. All conversions happen in your browser via a 200-line lookup table — open DevTools → Network and confirm. Nothing you type is uploaded.
How accurate are the conversions?
Conversion factors are taken from NIST and ISO standards (US customary units, SI). Floating-point precision means very small or very large values may show rounding past the 12th significant digit; that's a JavaScript limit, not a tool-precision limit. For most real-world use the answer is exact.
Why does Fahrenheit work differently?
Temperature uses an affine transform: °F = °C × 9/5 + 32. The +32 offset means you can't just multiply by a factor — you have to convert through Celsius. Same for Kelvin and Rankine. The math handles this correctly under the hood.
Does this support imperial and metric?
Yes — both. US customary (foot, mile, pound, gallon) and metric (meter, kilometer, kilogram, liter) are first-class. UK gallons (which are bigger than US gallons by ~20%) are listed separately.