Length Converter
Metres, feet, inches, miles and nautical miles, using the exact 1959 inch of 25.4 mm
Metres, feet, inches, miles and nautical miles, using the exact 1959 inch of 25.4 mm. No data leaves your browser – every conversion happens locally.
How length conversion works
Every unit here goes through the metre. Since the 1959 international yard and pound agreement, an inch is exactly 25.4 mm, which makes a foot exactly 0.3048 m and a mile exactly 1,609.344 m. So the conversions aren't approximations; the only rounding happens when the result is displayed.
The nautical mile is the odd one out. It's 1,852 m by definition and comes from navigation, where one nautical mile is roughly one arcminute of latitude. You'll see it in flight plans and sailing charts, rarely anywhere else.
One limitation: the tool takes a single unit at a time. For a height like 5 ft 9 in, enter 69 inches (or 5.75 feet) rather than two separate numbers.
Common length conversions
| 1 inch | 2.54 cm |
| 1 foot | 30.48 cm |
| 1 meter | 3.281 feet |
| 1 km | 0.621 miles |
| 1 mile | 1.609 km |
| 5 ft 10 in | 177.8 cm |
| 100 cm | 3 ft 3.4 in |
| 1 yard | 91.44 cm |
Things that trip people up
Height in feet + inches
Most converters take decimal feet, not feet + inches. 5 ft 9 in = 5.75 feet (9 ÷ 12 = 0.75). Or just enter 69 inches directly.
Running distances
A 5K is 3.107 miles. A 10K is 6.214 miles. A marathon (42.195 km) is 26.219 miles.
Worked examples
A 12 × 10 ft bedroom
12 ft is 3.66 m and 10 ft is 3.05 m. That's the figure a furniture site listing sizes in metres will want.
Half marathon distance
21.0975 km comes out at 13.11 miles, which is why race shirts round it to 13.1.
A4 paper
210 × 297 mm is 8.27 × 11.69 inches, slightly narrower and longer than US Letter (8.5 × 11 in).
Height chart: centimetres to feet and inches
Heights are the most common thing people convert here, and the answer they want is feet plus inches, not decimal feet. Each row divides by 2.54 to get inches, then splits off whole feet.
| Centimetres | Feet and inches | Decimal feet |
|---|---|---|
| 150 cm | 4 ft 11.1 in | 4.92 ft |
| 155 cm | 5 ft 1.0 in | 5.09 ft |
| 160 cm | 5 ft 3.0 in | 5.25 ft |
| 165 cm | 5 ft 5.0 in | 5.41 ft |
| 170 cm | 5 ft 6.9 in | 5.58 ft |
| 175 cm | 5 ft 8.9 in | 5.74 ft |
| 180 cm | 5 ft 10.9 in | 5.91 ft |
| 185 cm | 6 ft 0.8 in | 6.07 ft |
| 190 cm | 6 ft 2.8 in | 6.23 ft |
Where length conversions go wrong
The big one is reading 5.10 ft as 5 ft 10 in. Decimal feet aren't feet and inches: 5.10 ft is 61.2 inches, or 155.4 cm, while 5 ft 10 in is 177.8 cm. That's a 22 cm gap from one misplaced idea. If a form asks for feet, check whether it means decimal feet before you type.
A smaller trap catches surveyors. The US survey foot, used for some land records until NIST retired it at the end of 2022, is 1200/3937 m, about 2 parts per million longer than the international foot. On a single mile that's roughly 0.01 ft, so it only matters for state plane coordinates and long baselines. This tool uses the international foot.