Inches to Centimeters Converter
Convert inches to centimeters instantly. 1 inch = 2.54 cm exactly. Formula, table and why paper sizes reveal the difference.
Written by Rahman · Last reviewed
Quick answer
One inch equals exactly 2.54 centimeters, an internationally fixed figure since 1959. Multiply inches by 2.54 to get centimeters, so a 12-inch ruler measures 30.48 cm.
| Metre (m) | 0.0254 |
| Kilometre (km) | 0.0000254 |
| Decimetre (dm) | 0.254 |
| Centimetre (cm) | 2.54 |
| Millimetre (mm) | 25.4 |
| Micrometre (µm) | 25400 |
| Nanometre (nm) | 25400000 |
| Mile (mi) | 0.00001578282828 |
| Yard (yd) | 0.02777777778 |
| Foot (ft) | 0.08333333333 |
| Inch (in) | 1 |
| Nautical mile (nmi) | 0.00001371490281 |
| Light year (ly) | 2.684782e-18 |
in to cm conversion table
| in | cm |
|---|---|
| 1 in | 2.54 cm |
| 2 in | 5.08 cm |
| 3 in | 7.62 cm |
| 4 in | 10.16 cm |
| 5 in | 12.7 cm |
| 6 in | 15.24 cm |
| 7 in | 17.78 cm |
| 8 in | 20.32 cm |
| 9 in | 22.86 cm |
| 10 in | 25.4 cm |
| 20 in | 50.8 cm |
| 30 in | 76.2 cm |
| 40 in | 101.6 cm |
| 50 in | 127 cm |
| 60 in | 152.4 cm |
| 70 in | 177.8 cm |
| 80 in | 203.2 cm |
| 90 in | 228.6 cm |
| 100 in | 254 cm |
| 250 in | 635 cm |
| 500 in | 1270 cm |
| 1000 in | 2540 cm |
How to convert in to cm
Paper size is where the inch/centimetre split shows up in daily life: US Letter paper is 8.5 × 11 inches (21.59 × 27.94 cm), while the rest of the world uses the metric A4 standard, 21.0 × 29.7 cm. The two are close enough to look interchangeable and different enough that a document formatted for one prints awkwardly on the other.
Because 2.54 is exact, converting inches to centimetres never needs rounding at the input stage, and only the result gets rounded for display. That makes this direction the more "honest" one arithmetically; the reverse (cm to inches) is the direction that actually loses precision. A doctor's chart in a metric country records height in centimetres, while a US chart typically keeps feet and inches, so a patient's own sense of "how tall am I" often has to be translated between the two.
Frequently Asked Questions
How many centimeters is 1 inch?
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Exactly 2.54 cm, fixed by international agreement, not measured or rounded.