Unit Converter
Calculators & Converters
Convert between units across nine categories: length, mass, temperature, area, volume, speed, time, data, and energy. Bidirectional live conversion.
Runs entirely in your browserAbout Unit Converter
Unit conversion comes up constantly — whether you're cooking with a recipe in another country, doing engineering calculations, shipping internationally, or just settling a Fahrenheit-vs-Celsius argument. This converter covers nine categories with about fifty units total, and the inputs are bidirectional: change either field and the other updates.
Most units convert linearly through a base unit (multiply by a factor). Temperature is the exception — Celsius, Fahrenheit, and Kelvin relate via an offset and a slope, so the converter has a special-case formula. Data units include both binary (KiB = 1024 B) and decimal (kB = 1000 B) variants since both are commonly used but for different things. The conversion factors are sourced from SI definitions and standard reference tables. Everything runs in your browser.
How to use
- 1
Pick a category
Use the Category dropdown — length, mass, temperature, area, volume, speed, time, data, or energy.
- 2
Pick the two units
Choose the 'From' and 'To' units. The defaults are sensible pairs for each category (e.g. meters → feet, Celsius → Fahrenheit).
- 3
Type into either field
The other field updates live. Bidirectional editing means you can converge on the value from either direction.
- 4
Swap and copy
Use the swap button to reverse the direction. Use Copy to grab the converted value.
Examples
Meters to feet
Most common length conversion for engineering and construction.
Input
1 mOutput
3.280840 ftFahrenheit to Celsius
Temperature conversion (non-linear: subtract 32, multiply by 5/9).
Input
100 °FOutput
37.777778 °CMebibytes to megabytes
Binary vs decimal data units — the source of the famous storage discrepancy.
Input
1 MiBOutput
1.048576 MBFrequently asked questions
How accurate are the conversions?+
Conversion factors are sourced from SI definitions and standard tables. The output is accurate to about 6 decimal places, which exceeds the precision of nearly all everyday use.
Why are there two sets of data units?+
Binary prefixes (KiB, MiB, GiB) are exact powers of 1024 and are used by most operating systems. Decimal prefixes (kB, MB, GB) follow the SI standard (powers of 1000) and are what hard drive manufacturers use. The discrepancy is why a '1TB' drive shows ~931 GiB in your file manager.
Why does temperature need a special formula?+
Celsius and Fahrenheit have different zero points and different scales, so the conversion isn't a simple multiplier — it's `(F − 32) × 5/9` or `C × 9/5 + 32`. Kelvin shares Celsius's scale but with a different zero point.
Are imperial and US customary the same?+
Not always. The US gallon (3.785 L) and the imperial gallon (4.546 L) differ. We label them separately. Most other US/imperial units (pound, foot, mile) are identical.
Is anything sent to a server?+
No. All conversion factors and math run in your browser.
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