Orpheus

Inches to Centimetres

Convert inches to centimetres for forms, shipping and furniture.

Inputs
in

The number of inches to convert.

Centimetres
91.44cm
In metres
0.914m
1 in
2.54cm
6 in
15.24cm
12 in
30.48cm
24 in
60.96cm
centimetres = inches × 2.54

1 in = 2.54 cm

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Multiply inches by 2.54 to get centimetres. The relationship is exact by international definition, so a 36 inch width is precisely 91.44 centimetres with no rounding involved.

How to use Inches to CM Converter

  1. Enter the inches. Decimals are fine — enter 5.5 rather than 5 1/2.
  2. Read the centimetres. Shown to two decimals, with metres underneath for larger dimensions.

About converting inches to centimetres

Converting inches to centimetres comes up most often when something crosses a border — a shipping label, a customs form, a piece of furniture bought abroad, a specification written for one market and read in another. The arithmetic is exact and trivial. What is worth knowing is where the number you are converting is not a measurement at all. Timber sold as a two-by-four measures closer to 38 by 89 millimetres, because the nominal size refers to the rough-sawn dimensions before drying and planing. Pipe sizes are nominal in the same way, and a half-inch pipe has neither an inner nor an outer diameter of half an inch. Screen sizes are diagonal, so converting the diagonal tells you nothing about how much desk a monitor needs. Paper is the clearest case of two systems that simply do not line up: US Letter is 8.5 by 11 inches, which converts to 215.9 by 279.4 millimetres, while A4 is 210 by 297 — narrower and taller, which is why a document laid out for one prints with clipped margins on the other. For dimensions that matter, convert a measurement you took, and add clearance before trusting the fit.

Frequently asked questions

How many centimetres is 12 inches?
Exactly 30.48 centimetres, since a foot is twelve inches and an inch is defined as 2.54 centimetres. That is why a ruler marked 12 inches is usually also marked 30 cm rather than 30.5.
How do I enter a fraction like 5 1/2 inches?
As a decimal: 5.5. Common fractions convert simply — a quarter is 0.25, an eighth is 0.125, a sixteenth is 0.0625. Multiply the top number by the bottom and add it to the whole inches.
Why does my furniture not fit despite the conversion being right?
Because listed dimensions usually exclude handles, feet, doors that swing and the clearance needed to carry the item through a doorway. Convert the measurement, then add the gaps — the arithmetic is rarely what goes wrong here.
Are US and UK inches the same?
Yes, since 1959. Both use the international inch of exactly 2.54 centimetres. The United States retained a marginally different survey foot for land surveying, which differed by about two parts per million, and even that was retired in 2023.

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