Unit Conversion Calculators
Free unit converters for length, weight, temperature, and more. Convert between metric and imperial units instantly and accurately.
Definitions from BIPM and NISTLength
Calxy core engineScientific notation is supported, for example 1e6 or 2.5e-3. Thousands separators such as 1,000 are fine.
Popular shortcuts
Narrows both unit lists; the units already chosen stay listed.
cm to in
Exact definition0.393701 in
1 cm = 0.393701 in
About these units
Ordinary feet, yards and miles use international definitions. The separately labeled US survey foot is for legacy records only. A nautical mile is exactly 1,852 meters; it is not a constant minute of latitude on Earth.
Formula and calculation
Standard linear transformin = x × 0.393700787401575
in = 1 × 0.393700787401575 = 0.393701 inBase transformation: 1 cm = 0.01 m; 1 in = 0.0254 m. Ratio: 0.393700787401575.
Fractional and ruler equivalent
0 ft 0.39 in (nearest 0.01 inch)
0 3/8 inches (nearest 1/16 inch, ties upward).
Accuracy
Relationship: exact definition. Display: rounded to up to 6 decimal places, with scientific notation for very small or large values. More digits do not mean greater measurement accuracy; factors involving π or recurring fractions are approximations.
Definition sources
How we round and calculateReferences for the selected units and their conversion factors.
- International System of UnitsInternational Bureau of Weights and Measures (BIPM)
- SP 811 Appendix B.8: conversion factorsNational Institute of Standards and Technology (NIST)
Result in every supported unit31 units
| Unit | Result |
|---|---|
| Millimeter (mm) | 10 |
| Centimeter (cm) | 1 |
| Meter (m) | 0.01 |
| Kilometer (km) | 0.00001 |
| Micrometer (µm) | 10000 |
| Nanometer (nm) | 10000000 |
| Inch (in) | 0.393701 |
| Foot (ft) | 0.032808 |
| Yard (yd) | 0.010936 |
| Mile (mi) | 0.00000621371 |
| Nautical mile (nmi) | 0.00000539957 |
| Light-year (ly) | 1.057001e-18 |
| Astronomical unit (au) | 6.684587e-14 |
| US survey foot (legacy) (ftUS) | 0.032808 |
| Angstrom (Å) | 100000000 |
| Mil (0.001 inch) (mil) | 393.700787 |
| Microinch (µin) | 393700.787402 |
| Fathom (international) (fathom) | 0.005468 |
| Chain (international) (ch) | 0.000497097 |
| Rod (international) (rd) | 0.001988 |
| Exameter (Em) | 1.000000e-20 |
| Petameter (Pm) | 1.000000e-17 |
| Terameter (Tm) | 1.000000e-14 |
| Gigameter (Gm) | 1.000000e-11 |
| Megameter (Mm) | 1.000000e-8 |
| Hectometer (hm) | 0.0001 |
| Decameter (dam) | 0.001 |
| Decimeter (dm) | 0.1 |
| Picometer (pm) | 10000000000 |
| Femtometer (fm) | 1.000000e+13 |
| Attometer (am) | 1.000000e+16 |
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Popular conversion pairs
Frequently used calculations across commerce, science and everyday measurement.
- Centimeters to InchesConvert centimeter (cm) to inch (in), or swap units to reverse the calculation.
- Inches to CentimetersConvert inch (in) to centimeter (cm), or swap units to reverse the calculation.
- Kilograms to PoundsConvert kilogram (kg) to pound (lb), or swap units to reverse the calculation.
- Pounds to KilogramsConvert pound (lb) to kilogram (kg), or swap units to reverse the calculation.
- Celsius to FahrenheitConvert celsius (°C) to fahrenheit (°F), or swap units to reverse the calculation.
- Fahrenheit to CelsiusConvert fahrenheit (°F) to celsius (°C), or swap units to reverse the calculation.
- Kilometers to MilesConvert kilometer (km) to mile (mi), or swap units to reverse the calculation.
- Miles to KilometersConvert mile (mi) to kilometer (km), or swap units to reverse the calculation.
- US Fluid Ounces to MillilitersConvert fluid ounce (us) (fl oz) to milliliter (mL), or swap units to reverse the calculation.
- Milliliters to US Fluid OuncesConvert milliliter (mL) to fluid ounce (us) (fl oz), or swap units to reverse the calculation.
- Feet to MetersConvert foot (ft) to meter (m), or swap units to reverse the calculation.
- Meters to FeetConvert meter (m) to foot (ft), or swap units to reverse the calculation.
- Millimeters to InchesConvert millimeter (mm) to inch (in), or swap units to reverse the calculation.
- Grams to OuncesConvert gram (g) to ounce (oz), or swap units to reverse the calculation.
- Liters to US GallonsConvert liter (L) to gallon (us) (gal), or swap units to reverse the calculation.
- US Gallons to LitersConvert gallon (us) (gal) to liter (L), or swap units to reverse the calculation.
- MPH to KPHConvert mile per hour (mph) to kilometer per hour (km/h), or swap units to reverse the calculation.
- KPH to MPHConvert kilometer per hour (km/h) to mile per hour (mph), or swap units to reverse the calculation.
- Kilograms to StoneConvert kilogram (kg) to stone (st), or swap units to reverse the calculation.
- Stone to KilogramsConvert stone (st) to kilogram (kg), or swap units to reverse the calculation.
- US Cups to MillilitersConvert cup (us) (cup) to milliliter (mL), or swap units to reverse the calculation.
- US Tablespoons to MillilitersConvert tablespoon (us) (tbsp) to milliliter (mL), or swap units to reverse the calculation.
- Square Feet to Square MetersConvert square foot (ft²) to square meter (m²), or swap units to reverse the calculation.
- Acres to HectaresConvert acre (ac) to hectare (ha), or swap units to reverse the calculation.
- PSI to BarConvert pound per square inch (psi) to bar (bar), or swap units to reverse the calculation.
- Kilowatts to HorsepowerConvert kilowatt (kW) to horsepower (mechanical) (hp), or swap units to reverse the calculation.
- Horsepower to KilowattsConvert horsepower (mechanical) (hp) to kilowatt (kW), or swap units to reverse the calculation.
- Megabytes to GigabytesConvert megabyte (MB) to gigabyte (GB), or swap units to reverse the calculation.
- Knots to MPHConvert knot (kn) to mile per hour (mph), or swap units to reverse the calculation.
- Meters to YardsConvert meter (m) to yard (yd), or swap units to reverse the calculation.
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