Unit converter
Convert any unit to every other unit of its kind — 30 categories from length and pressure to fuel economy, flow rate and data — or just type “5 ft 7 in to cm”.
Open Unit converter →What is the unit converter?
A free, private converter that turns any unit into every other unit of the same kind. It covers 30 categories — length, area, volume, mass, temperature, time, speed, acceleration, force, pressure, energy, power, frequency, angle, digital storage, data rate, fuel economy, volumetric flow, density, torque, the common electrical quantities, illuminance, dynamic and kinematic viscosity, and screen and print typography. Conversions use the exact definitions (an inch is 2.54 cm, a pound is 0.45359237 kg), temperature is handled as an offset scale rather than a simple ratio, and L/100 km is correctly treated as the inverse of km/L and mpg. Everything runs in your browser, so nothing you type leaves your device and it works offline.
How to use Unit converter
- Pick a category — Choose what you are measuring — Length, Pressure, Fuel economy and so on. On a phone the categories sit in a drop-down.
- Enter a value and units — Type the value, then choose the unit to convert From and the unit To. Fractions such as 3/4 or 1 1/2 and numbers written as 1,5 or 1.234,5 are understood.
- Or type it in one go — Use Quick convert to write the whole thing, for example “5 ft 7 in to cm”, “100 km/h in mph” or “350 °F to °C”. The tool picks the category and units for you, and adds up mixed units like feet and inches.
- Read every unit at once — The table below lists the value in every unit of the category. Click any row to make it the target, and use Copy to put the result on your clipboard.
Frequently asked questions
How accurate are the conversions?
Factors come from the exact legal definitions wherever one exists, and results are shown to 12 significant digits by default. You can switch to 6 or 4 significant digits, two decimal places or scientific notation from the Precision menu.
Which gallon, cup and ton does it use?
Both are listed separately: US and UK (imperial) gallons, pints, quarts and fluid ounces; US and metric cups; and the metric tonne, US short ton and UK long ton.
Why does fuel economy behave differently?
Litres per 100 km measures fuel used per distance, while km/L and mpg measure distance per fuel. One is the reciprocal of the other, so doubling one halves the other. The tool converts through that reciprocal instead of a fixed factor.
What do “month” and “year” mean?
They are Gregorian averages — a year of 365.2425 days and a month of one twelfth of that. For calendar arithmetic between real dates, use the date calculator instead.
Is my data sent anywhere?
No. Every conversion happens locally in your browser and your last category, units and value are saved only on your device.
Tips
- Quick convert resolves ambiguous symbols from context — “12 pt to px” means points, while “2 pt to l” means pints.
- Mixed quantities add up automatically: “3 lb 4 oz to kg” or “2 h 30 min to min”.
- Oilfield units are included: barrels, bbl/min, bbl/d, ppg mud weight and specific gravity.
- Use the swap button between the two units to reverse a conversion instantly.