Length calculator: convert any unit
Enter a length, pick the unit it is in and the unit you want. The answer updates as you type, and the result panel also shows meters, centimeters, inches, feet, miles, and feet and inches.
- Converted length
- 3.048
10 feet (ft) = 3.048 meters (m).
- Meters (m)
- 3.048
- Centimeters (cm)
- 304.8
- Kilometers (km)
- 0.003048
- Inches (in)
- 120
- Feet (ft)
- 10
- Miles (mi)
- 0.001894
- Feet and inches
- 10 ft 0 in
Converted length: 3.048. 10 feet (ft) = 3.048 meters (m).
How to calculate
Converts a length between millimeters, centimeters, meters, kilometers, inches, feet, yards, miles, nautical miles, and more, with feet and inches.
Example with the default inputs (Length 10, From feet (ft), To meters (m)): 10 feet (ft) = 3.048 meters (m).
Method: converted = length × (meters per "From" unit) ÷ (meters per "To" unit)
- Meters per unit are the exact definitions in NIST SP 811: 1 in = 0.0254 m, 1 ft = 12 in, 1 yd = 3 ft, 1 mi = 5,280 ft, 1 nautical mile = 1,852 m, 1 mil = 0.001 in.
- The arithmetic is exact on the decimal you type; each answer is rounded once, and the page shows at most 6 decimal places.
- Feet and inches round the inches half up to 0.01 in; inches that round to 12 count as one more foot.
Worked examples
Each example is checked against the calculator on every build.
- Length 10, From feet (ft), To meters (m) gives Converted length 3.048, Inches (in) 120, Feet and inches 10 ft 0 in.Source: NIST SP 811 (2008), Appendix B.8: 1 ft = 0.3048 m exactly
- Length 1, From meters (m), To inches (in) gives Converted length 39.370079, Feet (ft) 3.28084, Feet and inches 3 ft 3.37 in.Source: NIST SP 811 (2008), Appendix B.8: 1 in = 0.0254 m exactly
- Length 5, From kilometers (km), To miles (mi) gives Converted length 3.106856, Meters (m) 5,000.Source: NIST SP 811 (2008), Appendix B.8: 1 mi = 1,609.344 m exactly
- Length 1, From nautical miles (nmi), To feet (ft) gives Converted length 6,076.115486, Meters (m) 1,852.Source: NIST SP 811 (2008), Appendix B.8: 1 nautical mile = 1,852 m exactly
- Length 178, From centimeters (cm), To feet (ft) gives Converted length 5.839895, Feet and inches 5 ft 10.08 in.Source: NIST SP 811 (2008), Appendix B.8: 178 ÷ 2.54 = 70.0787… in = 5 ft 10.08 in
How it works
Every unit has an exact size in meters. The converter turns the length into meters, then into the unit you want:
converted = length × (meters per "From" unit) ÷ (meters per "To" unit)
Meters per unit, all exact (NIST SP 811):
| Unit | Meters |
|---|---|
| nanometer (nm) | 0.000000001 |
| micrometer (µm) | 0.000001 |
| millimeter (mm) | 0.001 |
| centimeter (cm) | 0.01 |
| meter (m) | 1 |
| kilometer (km) | 1,000 |
| mil (0.001 in) | 0.0000254 |
| inch (in) | 0.0254 |
| foot (ft, 12 in) | 0.3048 |
| yard (yd, 3 ft) | 0.9144 |
| mile (mi, 5,280 ft) | 1,609.344 |
| nautical mile (nmi) | 1,852 |
The result panel also shows the length in meters, centimeters, kilometers, inches, feet, and miles, and in feet and inches.
Rules
- The length is 0 or more, up to 1,000,000,000,000 in the "From" unit. A negative length is not a length, so the field rejects it.
- The arithmetic is exact. The calculator reads the decimal you type as an exact fraction, multiplies and divides by the exact sizes above, and rounds only the final answer to the nearest double-precision number.
- The page shows at most 6 decimal places, rounded half up from the decimal value. This holds for up to 14 significant digits. A longer shown number (100,000,000 or more with 6 decimals) is rounded from the double-precision answer, so its last digit can be 1 off.
- Feet and inches: the exact length in inches is rounded half up to 0.01 in. Then the whole feet are the hundredths of an inch divided by 1,200 (rounded down), and the inches are what is left. Inches that round to 12.00 count as one more foot.
Worked examples by hand
10 ft to meters. 10 × 0.3048 = 3.048 m. In inches: 10 × 12 = 120 in, or 10 ft 0 in.
1 m to inches. 1 ÷ 0.0254 = 39.37007874 in. In feet: 1 ÷ 0.3048 = 3.280839895 ft. In feet and inches: 39.37 in is 3 ft and 3.37 in.
5 km to miles. 5,000 ÷ 1,609.344 = 3.106855961 mi.
1 nautical mile to feet. 1,852 ÷ 0.3048 = 6,076.115485564 ft.
178 cm to feet. 1.78 ÷ 0.3048 = 5.839895013 ft. In inches: 178 ÷ 2.54 = 70.0787 in, rounded to 70.08 in, which is 5 ft and 10.08 in.
Other questions people ask
How many centimeters are in an inch?
Exactly 2.54. Since 1959 the inch is defined as 0.0254 m (NIST SP 811), so 12 inches are 30.48 cm.
How many feet are in a meter?
1 m is 1 ÷ 0.3048 = 3.280839895 ft, or 3 ft 3.37 in. A foot is exactly 0.3048 m.
How many kilometers are in a mile?
A mile is exactly 1.609344 km (5,280 ft). So 5 km is 5 ÷ 1.609344 = 3.106856 miles.
What is a nautical mile?
A nautical mile is exactly 1,852 m by international agreement, about 6,076.1 ft or 1.15078 statute miles. Ships and aircraft use it, with speed in knots (nautical miles per hour).
What is a mil?
A mil (also called a thou) is one thousandth of an inch, 0.0254 mm. Machinists and sheet-metal and plastic-film sizes use it. It is not a millimeter.
How do I turn centimeters into feet and inches?
Divide by 2.54 to get inches, then take whole feet (12 inches each) and keep the rest as inches. 178 cm is 70.08 in, which is 5 ft 10.08 in. The result panel does this for you.