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Inches to centimeters (in to cm)

Type a value in inches and get the result in centimeters instantly — with the exact factor, a step-by-step formula and a table of common values.

Sources: NIST — Guide to the SI, Appendix B.8 (conversion factors: inch, foot, yard, mile)

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How to convert inches to centimeters

1 in = 2.54 cm
1 cm = 0.3937008 in

To convert inches to centimeters, multiply the value by 2.54.

Example: 12 in × 2.54 = 30.48 cm.

Inches to centimeters conversion table

Inches (in)Centimeters (cm)
0.51.27
12.54
25.08
37.62
410.16
512.7
615.24
820.32
1025.4
1230.48
2460.96
3691.44

Related conversions

Inches to centimeters runs the same conversion in the direction most useful to a metric audience reading a US spec sheet or DIY guide. A clean example: 12 in — a standard ruler length — converts to exactly 30.48 cm, since both units are fixed fractions of the meter and the arithmetic carries no rounding.

This pair comes up constantly around US furniture, appliances and tools sold or documented with inch measurements, and around screen sizes: a monitor or TV’s diagonal is quoted in inches everywhere, but shoppers outside the US often want the equivalent width and height in centimeters to check it’ll actually fit a desk or wall unit.

It also matters in home improvement and woodworking, where US tool and lumber measurements (inches, often in fractions like 3/4 in) need converting to centimeters or millimeters for metric plans or hardware.

FAQ

How many centimeters is 12 inches?

12 in equals exactly 30.48 cm. This is exact, not rounded — 1 inch is defined as exactly 2.54 cm, so 12 × 2.54 = 30.48.

How do I convert a fractional inch measurement, like 3/4 inch, to centimeters?

Convert the fraction to a decimal first (3/4 = 0.75), then multiply by 2.54: 0.75 × 2.54 = 1.905 cm. The same approach works for any fraction commonly used in US tools and lumber — eighths, sixteenths, and so on.

Why is 1 inch exactly 2.54 cm and not a rounder number?

Because the exact value was fixed by international agreement in 1959, choosing 2.54 cm specifically so that the inch, foot, yard and mile would all convert cleanly to and from metric units used in science and industry at the time. It isn’t rounded — it’s the legal definition.

Are inches used the same way worldwide?

The unit itself — 2.54 cm — is standardized worldwide today. What differs is where it’s used day to day: the US relies on inches for everyday measurement, while most other countries reserve it mainly for screen sizes, tire dimensions and a handful of specialist trades, using centimeters or millimeters everywhere else.

Sources