Unit converter
Convert length, weight, temperature, volume, area, speed, pressure, data and time in one place.
- ๐บ๐ธ US federal & state rules
- NIST SP 811 conversion factors
- See sources
in to cm
2.54 cm
1 in = 2.54 cm
- 1 in
- 2.54 cm
- 1 cm
- 0.3937007874 in
Results are rounded to 10 significant digits.
Common values, in to cm
| 0.5 in | 1.27 cm |
|---|---|
| 1 in | 2.54 cm |
| 2 in | 5.08 cm |
| 3 in | 7.62 cm |
| 4 in | 10.16 cm |
| 5 in | 12.7 cm |
| 10 in | 25.4 cm |
| 12 in | 30.48 cm |
| 20 in | 50.8 cm |
| 25 in | 63.5 cm |
| 50 in | 127 cm |
| 100 in | 254 cm |
| 1,000 in | 2,540 cm |
1 in in every unit
| Inches (in) | 1 in |
|---|---|
| Feet (ft) | 0.08333333333 ft |
| Yards (yd) | 0.02777777778 yd |
| Miles (mi) | 0.00001578282828 mi |
| Millimeters (mm) | 25.4 mm |
| Centimeters (cm) | 2.54 cm |
| Meters (m) | 0.0254 m |
| Kilometers (km) | 0.0000254 km |
| Nautical miles (NM) | 0.00001371490281 NM |
Show the math
| To m | 1 in ร 0.0254 = 0.0254 m |
|---|---|
| To cm | 0.0254 m รท 0.01 = 2.54 cm |
What to do next
How it works
Every unit is first turned into a base unit (meters, kilograms, liters, square meters, meters per second, pascals, bytes or seconds), then divided by the factor of the unit you want. Temperature is the exception: it goes through kelvin and adds or subtracts an offset, because 0 ยฐF and 0 ยฐC are not the same point.
The factors come from NIST Special Publication 811. Most US customary units are defined from two numbers: the inch (exactly 2.54 cm) and the pound (exactly 0.45359237 kg). A US gallon is exactly 231 cubic inches.
Handy length factors
| 1 in equals | Value |
|---|---|
| Feet (ft) | 0.08333333333 ft |
| Yards (yd) | 0.02777777778 yd |
| Miles (mi) | 0.00001578282828 mi |
| Millimeters (mm) | 25.4 mm |
| Centimeters (cm) | 2.54 cm |
| Meters (m) | 0.0254 m |
| Kilometers (km) | 0.0000254 km |
| Nautical miles (NM) | 0.00001371490281 NM |
Sources
Rules applied as of 2026-10-19. See the sources below for details.
- NIST SP 811, Appendix B.8: Factors for units listed alphabeticallyChecked 2026-10-19
- NIST: U.S. survey foot retired (acre now uses the international foot)Checked 2026-10-19
Frequently asked questions
What can I convert here?
Length, weight, temperature, volume, area, speed, pressure, data storage and time. Pick the kind first and the unit lists change to match.
How accurate are the results?
Units with an exact legal definition, like 1 inch = 2.54 cm and 1 lb = 0.45359237 kg, use that exact value. The answer is rounded to 10 significant digits.
Are cups and gallons US or UK?
US customary. A US gallon is 3.785 L and a UK imperial gallon is 4.546 L. The imperial gallon is listed separately under volume.
Why does my 1 TB drive show 931 GB?
The maker counts 1 TB as 10^12 bytes, but Windows divides by 1,024 three times. Switch the data storage setting to 1,024 to see the number Windows shows.