Length Converter

What units of length are supported?

Thirteen units are available. Metric: nanometer (nm), micrometer (μm), millimeter (mm), centimeter (cm), decimeter (dm), meter (m) and kilometer (km). Imperial and US customary: inch (in), foot (ft), yard (yd) and mile (mi). Plus two older sea and road units: the nautical mile (M) and the league (lea).

Each conversion first turns your value into meters and then into the target unit. The size of every unit in meters is fixed by definition:

Results are rounded to nine decimal places with commas in the whole part and no trailing zeros. A result too small to display normally appears in exponent form, such as 1e-9.

Imperial versus metric units of length

The metric system is decimal. Moving between its units is a matter of multiplying or dividing by a power of ten: 1 km is 1,000 m, 1 m is 100 cm and 1 cm is 10 mm. The imperial system grew from older measures and uses irregular steps: 12 inches in a foot, 3 feet in a yard and 1,760 yards in a mile.

Today the two systems are tied together. The inch is defined as exactly 25.4 millimeters, and every other imperial length follows from it, so converting between them is exact arithmetic rather than approximation. The nautical mile, 1,852 meters, was set by international agreement so that it matches about one minute of latitude. The league here is taken as three statute miles.

Length conversion examples

Feet to yards. There are 3 feet in a yard, so divide by 3. A 30 ft fence is 30 ÷ 3 = 10 yd. Through meters the converter gets the same result: 30 × 0.3048 ÷ 0.9144 = 10.

Meters to yards. Divide by 0.9144. A 100 m sprint track is 100 ÷ 0.9144 = 109.3613 yd, so the 100 m race is about 9 yards longer than the 100-yard dash.

Meters to feet. Divide by 0.3048. A 100 m track is 100 ÷ 0.3048 = 328.084 ft.

Kilometers to miles. Divide by 1.609344. The 10 km race is 10 ÷ 1.609344 = 6.2137 miles.

Nautical miles to kilometers. Multiply by 1.852. A ship covering 250 nautical miles has traveled 463 km.

Length conversion table

How much is 1 meter in the other units, and how much is one of each unit in meters:

Quick estimates: 1 inch ≈ 2.54 cm, 1 foot ≈ 30.5 cm, 1 yard ≈ 0.91 m, 1 mile ≈ 1.61 km, 1 nautical mile ≈ 1.15 miles.

Tips for accurate conversions

• Check the mile. This tool uses the international mile of 1,609.344 m. Old US survey measurements use a slightly different foot, but the gap is about two parts per million and does not matter for everyday work.
• Keep the unit symbols straight. M here is the nautical mile, m is the meter, and mi is the statute mile.
• Use exact factors. Rounding 0.3048 to 0.3 makes a 100 ft length look 1.6% shorter than it is.

For body measurements in feet and inches, the height converter has charts for people's heights, and the metric converter is useful for working through the decimal prefixes.