Convert centimetres to inches
Move measurements from metric to imperial in one click.
Calculator inputs
Results
Enter your values and press “Calculate” to see the result.
In short
- What it calculates
- Move measurements from metric to imperial in one click.
- Formula used
inches = centimetres ÷ 2.54- Example
- 100 cm to inches:
Centimetres to inches converter
Buying from international shops or filling in an English-language spec sheet means quoting measurements in inches, even if you took them with a metric tape.
How it works
The centimetres are divided by 2.54. To express the answer in fractions of an inch, round to the nearest fraction with denominator 8, 16 or 32.
Formula
inches = centimetres ÷ 2.54
1 cm = 0.393701 in
10 cm ≈ 3.94 in
Worked example
100 cm to inches:
100 ÷ 2.54 = 39.37 inches
A metre is practically 39 and a half inches.
Explanation
Fractions are the norm, not decimals
An English-language catalogue does not say 1.27 cm: it says half an inch. Measurements are expressed in halves, quarters, eighths and sixteenths, and an American tape measure is graduated that way. Converting to decimals is useful for calculating, but when buying you have to translate back to the nearest fraction.
The quick equivalence
A centimetre is roughly four tenths of an inch. To estimate mentally, divide centimetres by 2.5: 20 cm is about 8 inches, 30 cm about 12. The error from using 2.5 instead of 2.54 is one and a half per cent, enough for a rough idea but not for cutting timber.
Clothing and shoe sizes
English-language sizes are not direct conversions from centimetres: each manufacturer uses its own table. Trouser waists are usually in real inches, but a shirt or shoe size cannot be deduced by measuring. Check the specific brand's chart.
DIY and precision
In wood and metal, a millimetre matters. Rounding a conversion to the nearest eighth of an inch introduces up to 1.6 mm of error, which shows in a joint.
Frequently asked questions
How do I write the result as a fraction?
Multiply the decimal part by 16 and round: 0.37 × 16 = 5.9, so 39.37 in ≈ 39 and 6/16, that is 39 3/8 inches.
Is there a quick trick?
Divide by 2.5 and shave a little off: 100 / 2.5 = 40, and the real value is 39.4.
How do I turn a decimal into an inch fraction?
Multiply the decimal part by 16 and round: 0.375 inches is six sixteenths, that is three eighths.
Can I work out my shoe size by measuring my foot?
Only approximately. Each manufacturer uses its own chart, so check the one for that specific model.
Need to calculate something else?
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