Unit converter
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1 centimeter = 0.3937007874 inches
Formula: inches = centimeters ÷ 2.54
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Popular conversions
Each has its own page with the formula, a quick reference table and worked examples.
- cm → in
- in → cm
- mm → in
- ft → m
- m → ft
- km → mi
- mi → km
- kg → lb
- lb → kg
- g → oz
- oz → g
- st → kg
- °C → °F
- °F → °C
- l → gal
- gal → l
- ml → fl oz
- fl oz → ml
- cup → ml
- ft² → m²
- ac → ha
- km/h → mph
- mph → km/h
- MB → GB
- GB → TB
Metric, imperial and US units
Most of the world measures in the metric system, where units scale by powers of ten: 1,000 meters in a kilometer, 1,000 grams in a kilogram, 1,000 milliliters in a liter. That makes conversions inside the system a matter of moving the decimal point.
The United States uses US customary units (inches, feet, pounds, gallons) and the United Kingdom still uses some imperial units (miles, pints, stone). Both come from older English measures, which is why 12 inches make a foot and 16 ounces a pound. Since 1959 they have all been defined in metric terms, so every conversion here is exact.
Watch out for volumes: US and imperial gallons, pints and fluid ounces are different sizes. And in the kitchen, remember that ounces of weight and fluid ounces of volume are not the same thing.
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Frequently asked questions
How accurate are the conversions?
They use the official definitions, most of which are exact: an inch is exactly 2.54 cm, a pound exactly 0.45359237 kg and a US gallon exactly 3.785411784 liters. Results are shown with up to 10 significant digits, which is more precision than any everyday use needs.
Which countries use the imperial system?
The United States uses US customary units for most everyday measurements. The United Kingdom uses a mix: miles and pints are still common, while most other measurements are metric. Almost every other country uses the metric system.
Are US and UK units the same?
Lengths and weights are the same, but volumes are not. A US gallon is about 3.785 liters and an imperial gallon about 4.546 liters, and pints and fluid ounces differ too. UnitFlipr labels which one each unit is.
Can I enter decimals with a comma?
Yes. Both 1.5 and 1,5 work, and so do numbers with thousands separators like 1,000.5.
Is my input stored anywhere?
No. Conversions run entirely in your browser, and nothing you enter is sent to a server.