About the Unit Converter
A free all-in-one unit converter built for everyday use — cooking, travel, coding, studying, and more.
What it is
The Unit Converter handles twelve measurement categories in one place. Pick a category, choose your units, type a value — the result appears instantly. Edit either side and the other updates live; a swap button flips the direction in one tap. No page reloads, no sign-up, no data sent anywhere.
Each category also shows a panel of common conversions so you can grab frequently needed answers without typing at all.
Categories supported
Length
km, m, cm, mm, µm, mi, yd, ft, in, nautical mile
Weight / Mass
tonne, kg, g, mg, lb, oz, stone, US ton
Temperature
Celsius, Fahrenheit, Kelvin, Rankine
Volume
L, mL, m³, US gal, qt, pt, fl oz, imp gal, cup, tbsp, tsp
Area
km², m², cm², hectare, mi², acre, yd², ft², in²
Speed
m/s, km/h, mph, ft/s, knot, Mach
Time
year, week, day, hour, minute, second, ms, µs
Digital Storage
bit, byte, KB, MB, GB, TB, PB, Kb, Mb, Gb
Energy
J, kJ, cal, kcal, Wh, kWh, eV, BTU, ft·lb
Pressure
Pa, kPa, MPa, bar, mbar, atm, psi, Torr
Angle
degree, radian, gradian, arcminute, arcsecond, turn
Fuel Economy
L/100 km, km/L, MPG (US), MPG (Imperial)
How conversion works
All linear conversions go via a base unit — for example, length converts through metres. Any value is first converted to the base, then converted to the target. This approach keeps all factor relationships exact and makes it trivial to add new units.
Temperature is the exception: Celsius, Fahrenheit, Kelvin, and Rankine each have an offset, so they use explicit formulas (e.g. °F = (°C × 9/5) + 32) rather than a single scale factor. The base unit for temperature is Celsius.
Fuel economy is also non-linear because L/100 km and MPG are reciprocal scales. The converter applies the correct reciprocal transformation for each direction.
Digital storage uses binary prefixes (IEC): 1 KB = 1024 bytes, 1 MB = 1024 KB, and so on. Bit-rate units (Kb, Mb, Gb) use SI decimal factors (1 Mb = 1,000,000 bits).
Who it's for
Travellers
Convert km to miles, Celsius to Fahrenheit, and litres to gallons when abroad.
Students & researchers
Switch between SI and imperial for physics, chemistry, and engineering problems.
Cooks & bakers
Convert between cups, tablespoons, ml, and grams when following international recipes.
Developers & IT
Convert between bits, bytes, MB, GB, and TB when working with storage or bandwidth.
Privacy
All conversions run entirely in your browser using JavaScript. No values are stored, logged, or sent to a server. Close the tab and everything is gone.