Length Converter
Convert between miles, kilometers, feet, meters, inches, centimeters, and more.
All conversions
This length converter moves between ten units — metres, kilometres, centimetres, millimetres, micrometres, miles, yards, feet, inches, and nautical miles — through a single base unit, the metre. Type a value in one unit and the others update together.
Every factor here is exact by definition except the mile and the nautical mile, which are fixed by international agreement at 1609.344 m and 1852 m. That matters for survey and long-distance work, where a rounded factor accumulates error. For two-dimensional and three-dimensional measures, use the area converter and volume converter.
How to calculate length units
- Enter the number and choose its unit in the From field.
- The converter multiplies by that unit's metre factor.
- Divide by the target unit's factor to get the result.
- For height, convert to inches and split: 70.87 in is 5 ft 10.87 in (divide by 12, then multiply the remainder by 12).
Example
180 cm to feet: 180 × 0.01 = 1.80 m, and 1.80 / 0.3048 = 5.9055 ft. The 0.9055 ft is 0.9055 × 12 = 10.87 in, so 180 cm is 5 ft 10.9 in — usually written as 5 ft 11 in.
Length conversion formula
value_m = value × factor. target = value_m / factor_target. 1 in = 0.0254 m exactly; 1 ft = 0.3048 m; 1 yd = 0.9144 m; 1 mi = 1609.344 m; 1 nmi = 1852 m.
How to use this calculator
- Pick the source unit in the From list.
- Enter the value; the To field and the full conversion table below update immediately.
- Read any other unit straight from the table, which converts the same value into every supported unit at once.
- The URL keeps the value and both units, so a conversion can be bookmarked or shared.
Metric vs. imperial: what is exact
Since 1959 the inch is exactly 2.54 cm, which fixes the foot at 0.3048 m, the yard at 0.9144 m, and the mile at 1609.344 m. The older US survey foot — 1200/3937 m — is about 0.6 parts per million longer, or 0.6 mm per kilometre, and was retired at the end of 2022. The metric side is simpler still: every prefix is a power of ten, so a conversion is a decimal shift.
Common length conversions
| From | To | Multiply by |
|---|---|---|
| 1 inch | centimetres | 2.54 |
| 1 foot | metres | 0.3048 |
| 1 yard | metres | 0.9144 |
| 1 mile | kilometres | 1.609344 |
| 1 nautical mile | kilometres | 1.852 |
| 1 centimetre | inches | 0.393701 |
| 1 metre | feet | 3.280840 |
| 1 kilometre | miles | 0.621371 |
Exact factors. Divide instead of multiply to go the other way.
Why nautical miles are not miles
A nautical mile is one minute of latitude — 1852 m by definition since 1929. That is why aviation and marine charts use it: one knot is one nautical mile per hour, and one minute of latitude on the chart is one mile over the water. A statute mile is 1609.344 m, so the nautical mile is about 15% longer.
Rounding and significant figures
A conversion cannot add precision. Five feet is exactly 152.4 cm, but a measurement of 5 ft taken to the nearest inch is really somewhere between 151 and 154 cm. Keep the same number of significant figures as the original measurement and round only at the end — chaining rounded conversions is how a result drifts by a whole centimetre.
Common mistakes
- Multiplying where you should divide. 180 cm is 5.9 ft, not 70.9 ft — 70.9 is the figure in inches.
- Chaining rounded conversions. Convert once from the original unit; three roundings can shift a result by a centimetre.
- Using 1609 m for a mile over long distances. The 0.344 m error becomes 55 m over 100 miles.
FAQ
How many centimetres are in an inch?
Exactly 2.54. The inch has been defined that way since 1959, so 12 in is 30.48 cm and 1 m is 39.3701 in.
How do I convert cm to feet and inches?
Divide by 30.48 for feet, then multiply the decimal part by 12 for inches. 180 cm / 30.48 = 5.906 ft, so 5 ft and 0.906 × 12 = 10.9 in.
How many metres is a foot?
Exactly 0.3048 m. Going the other way, one metre is 3.28084 ft.
How many feet are in a mile?
5,280 — that is 1760 yards, and 5280 × 0.3048 = 1609.344 m.
Is a nautical mile longer than a mile?
Yes, by about 15%: 1852 m against 1609.344 m. It equals one minute of latitude, which is why charts use it.
How many inches is 5 ft 10?
70 in, or 177.8 cm. Multiply feet by 12, add the inches, then multiply by 2.54.
How do I convert miles to kilometres quickly?
Multiply by 1.6 for an estimate: 60 mi gives 96 km against an exact 96.56 km, about 0.6% low. Use 1.609 when the number matters.
Why is the metric system easier to convert?
Because prefixes are powers of ten: kilometres to metres is ×1000. Imperial units use 12, 3, 1760, and 5280, so each step needs its own factor.