General & Math

Unit converter

Switch between everyday measurement systems without mixing incompatible units. Convert length, mass or temperature, then swap the source and destination for a reverse conversion. Area conversion remains available in its own tool with square units and Korean pyeong.

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Result

A QUICK GUIDE

How to use

Choose Length, Mass or Temperature, then enter a value using a dot for the decimal point.
Choose the source and destination units and Calculate. Swap units reverses the selected units while preserving your input value; it clears the previous result.
Length includes m, km, cm, mm, in, ft, yd and mi. Mass includes kg, g, mg, lb and oz. Temperature includes Celsius (C), Fahrenheit (F) and kelvin (K). Mass is non-negative; signed length values are allowed.
Factors: 1 in = 0.0254 m, 1 ft = 0.3048 m, 1 yd = 0.9144 m, 1 mi = 1609.344 m, 1 lb = 0.45359237 kg and 1 oz = 0.028349523125 kg (avoirdupois). These are international units, not US survey feet or troy ounces.
Temperature uses K = C + 273.15 and F = C × 9/5 + 32. Values below 0 K, -273.15 C or -459.67 F are rejected. Results use floating-point arithmetic and up to 12 significant digits.

Worked examples

1 m → cm

100 cm

A metre contains one hundred centimetres.

32 F → C

0 C

The Fahrenheit freezing point converts to zero degrees Celsius.

Questions & answers

Is an ounce a fluid ounce?

No. oz here is an avoirdupois unit of mass. Fluid ounces measure volume and cannot be converted to mass without knowing the material’s density.

Where is area conversion?

Use the separate area-unit converter for m², ft², hectares, acres and pyeong. Squared units require squared length conversion factors.

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