Length Unit Converter (cm, inch, ft, mile)

Converts a length into millimetres, centimetres, metres, kilometres, inches, feet, yards and miles. Give the value with its unit, so inches convert to centimetres just as easily as the other way round.

Explanation

Enter a length and choose its unit, and every other unit follows. The input unit is yours to pick, so inches convert to centimetres exactly as easily as centimetres convert to inches.

The definitions

Since the international agreement of 1959, the imperial units have been tied to the metre by exact values, not approximations.

1 inch = 2.54 cm exactly
1 ft = 12 inch = 30.48 cm
1 yd = 3 ft = 91.44 cm
1 mile = 1760 yd = 1609.344 m

Example

Convert 10 inches.

10 \times 2.54 = 25.4\ \text{cm}

That is 254 mm, 0.254 m or 0.8333 ft. Enter 25.4 cm instead and you get 10 inches back.

Where it is used

Screen sizes are quoted in inches: a 32-inch television measures 81.28 cm across the diagonal
Wheel and tyre sizes are in inches
A marathon is 26.2 miles, or 42.195 km

Watch out

The Japanese shaku is not in this table. It is 10/33 m, about 30.3 cm, which is close to a foot (30.48 cm) but not the same. The two are easy to confuse.