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Conversion

Unit Converter

Convert between metric, imperial and US customary units for length, weight, temperature, area, volume, speed, time and digital storage — with the exact formula for every conversion.

Results

1 cm =0.3937007874 incentimeters → inches
1 cm0.3937007874 in
1 in2.54 cm
Formula
in = cm × 0.3937007874
1 cm in other units
UnitValue
millimeters (mm)10
meters (m)0.01
kilometers (km)0.00001
inches (in)0.3937007874
feet (ft)0.03280839895
yards (yd)0.01093613298
miles (mi)0.000006213711922
nautical miles (nmi)0.000005399568035

How it works

  1. Choose what you are measuring.
  2. Enter the value.
  3. Choose the unit to convert from and the unit to convert to.

Formula

result = value × (from factor ÷ to factor)

Each unit is defined by its exact factor relative to a base unit (for example 1 inch = 0.0254 m by international definition). Temperature scales also include an offset, so °F = °C × 9/5 + 32.

Example

A running route is 5 miles long. How far is that in kilometers?

Inputs

Measurement
Length
Value
5
From
miles (mi)
To
kilometers (km)

Result

5 mi =8.04672 kmmiles → kilometers
1 mi1.609344 km
1 km0.6213711922 mi
Load this example into the calculator →

Frequently asked questions

How exact are the conversions?

Factors use the exact international definitions (for example 1 pound = 0.45359237 kg and 1 inch = 2.54 cm). Results are shown to 10 significant digits.

Are gallons US or imperial?

Volume units such as gallons, quarts, pints, cups and fluid ounces use US customary definitions.

Why are there two kinds of kilobytes?

Decimal units (KB, MB, GB) use powers of 1,000. Binary units (KiB, MiB, GiB) use powers of 1,024, which is how many operating systems report memory and file sizes.

How long is a month or a year here?

Months and years use average Gregorian lengths: a year is 365.2425 days and a month is one twelfth of that.