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Burrows Tools

Unit Converter

Six kinds of measurement in one place: length, weight and mass, temperature, area, volume, and speed. Type an amount, pick the units, and the answer appears as you type — along with a table of the same quantity in every other unit of that category, because the second question is usually 'and how much is that in...'. The factors are the exact international definitions rather than the rounded ones textbooks use: an inch is 0.0254 metres, a pound is 0.45359237 kilograms, a US gallon is 3.785411784 litres. Temperature is handled separately, since Celsius, Fahrenheit, Kelvin, and Rankine are offset scales rather than simple multiples — which is why −40 °C really is −40 °F. Results are rounded only at the very end, so repeated conversions do not drift. Everything runs in your browser, with no network request and nothing stored.

Centimeters to Inches

0.3937007874 in

1 cm = 0.3937007874 in

1 cm in every length unit
UnitValue
Nanometers (nm)10,000,000
Micrometers (µm)10,000
Millimeters (mm)10
Centimeters (cm)1
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

Conversion factors are the exact international definitions. Everything is calculated in your browser — nothing is sent anywhere.

How to use the unit converter

  1. Choose what you are measuring: length, weight, temperature, area, volume, or speed.
  2. Type the amount, then pick the unit you have and the unit you want.
  3. Read the converted value, or use Swap to reverse the two units.
  4. Scan the table underneath for the same amount in every other unit of that category.

Frequently asked questions

How many centimeters are in an inch?
Exactly 2.54. The inch has been defined as 0.0254 metres by international agreement since 1959, so this is a definition rather than a measurement, and the same is true of the foot (0.3048 m), yard (0.9144 m), and mile (1609.344 m).
Why is temperature handled differently?
Because its scales do not start at the same zero. Length and weight are proportional — double the metres, double the feet — but 20 °C is not twice as hot as 10 °C. Each temperature unit therefore carries its own conversion, which is what makes −40 come out as −40 in both Celsius and Fahrenheit.
Are the results rounded?
The calculation keeps 14 significant digits and the display shows 10, which is far beyond the precision of anything you are likely to be measuring. Rounding happens once, at the end, so converting back and forth does not accumulate error.
Which gallon does it use?
Both. US liquid gallons and imperial (UK) gallons are separate units in the volume list, because they differ by about 20 percent — a difference that has ruined more than one recipe and more than one fuel-economy comparison.
Is anything sent to a server?
No. The conversion table ships with the page and the arithmetic runs in your browser, so the tool keeps working with the network switched off.

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