Unit Converter

One converter for everyday units

Pick a category, type a value, and every other unit in that category updates at once — you also get a full list below so you can read several answers without switching back and forth.

Categories covered

• Length — m, km, cm, mm, mile, yard, foot, inch, nautical mile
• Weight / mass — kg, g, mg, tonne, pound, ounce, stone, 市斤, 市两
• Area — m², km², hectare, 亩, acre, ft², in², mile²
• Volume — litre, ml, m³, US gallon/quart/pint/cup/fl oz/tbsp/tsp, UK gallon
• Speed — m/s, km/h, mph, ft/s, knot, Mach
• Digital storage — byte → TB, plus binary MiB/GiB
• Time — ms → year
• Pressure — Pa, kPa, MPa, bar, mbar, atm, psi, mmHg
• Energy — J, kJ, calorie, kcal, Wh, kWh, BTU, eV
• Temperature — Celsius, Fahrenheit, Kelvin, Rankine (handled with the correct offset formulas, not a simple ratio)

Accuracy notes

• Conversion factors are exact where the definition is exact (inch = 25.4 mm, pound = 0.45359237 kg, calorie = 4.184 J).
• Chinese units follow the mainland standard: 1 市斤 = 0.5 kg, 1 亩 = 666.67 m².
• Digital storage uses decimal prefixes by default (1 GB = 1000 MB), with binary MiB/GiB listed separately — the difference is exactly why a "1 TB" drive shows ~931 GiB in Windows.
• Results are displayed to 12 significant digits.

Privacy

All conversion is local arithmetic in your browser: nothing to upload, nothing logged.

FAQ

Why does my 1 TB drive show less space?

Drive makers use decimal units (1 TB = 1000 GB) while operating systems often report binary GiB. 1 TB ≈ 931 GiB — nothing is missing, the units differ.

Are Chinese units supported?

Yes: 市斤 and 市两 for mass, 亩 for area, both using the mainland standards (1 斤 = 0.5 kg, 1 亩 ≈ 666.67 m²).

Is the temperature conversion accurate?

Yes. Temperature uses the correct offset formulas (°F = °C × 9/5 + 32), not a simple multiplication, so -40 °C correctly equals -40 °F.