Inches to Cm Converter

How to convert inches to centimeters

centimeters = inches × 2.54

The 2.54 isn't a rounded convenience number — it's exact. The inch has been defined as exactly 25.4 millimeters since the 1959 international yard and pound agreement, and a centimeter is ten millimeters, so one inch is exactly 2.54 cm. Nothing in the multiplication needs rounding until the final display.

Worked example, 12 in: 12 × 2.54 = 30.48 cm. The leftover 0.48 cm becomes millimeters: 0.48 × 10 = 4.8 mm, so 12 in reads as 30 cm 4.8 mm — which is how a metric tape measure or a European furniture spec would actually print it.

Tape measures don't read in decimals

A US tape reads 12 7/16", not 12.4375". Most converters make you divide 7 by 16 yourself, and the usual slip is typing 12.7 — which converts to 32.26 cm instead of the true 31.59 cm, nearly 7 mm of error on a cut you can't undo. Pick the fraction here and the division happens before the conversion.

The fractions you'll meet most often, in metric: 1/16" = 1.59 mm, 1/8" = 3.18 mm, 1/4" = 6.35 mm, 3/8" = 9.53 mm, 1/2" = 12.70 mm.

When the 2.5 shortcut is fine — and when it isn't

Rounding 2.54 down to 2.5 costs 0.04 cm per inch, which is invisible on a 10-inch bookshelf. It stops being invisible at scale: 100 in comes out at 250 cm against the true 254 cm — a 4 cm gap, enough to ruin a cut list or a fitted cover. Keep the full factor whenever the result is something you'll cut, order, or ship.

How to use this converter

1. Type the whole inches (12 in is filled in, so the page shows a result immediately).
2. Add a fraction only if your measurement came off a tape measure.
3. Read the centimeters line — that's the number for specs, forms, and orders.
4. Open the chart to see common inch sizes converted for you.

Frequently asked questions

How many cm is 1 inch?

2.54 cm, exactly. One inch is defined as 25.4 mm, and there are 10 mm in a centimeter.

What is 12 inches in cm?

30.48 cm (30 cm 4.8 mm). It's the default value on this page, so you can check it without typing anything.

How do I convert a fraction like 7/16 inch?

Divide the fraction into a decimal first — 7 ÷ 16 = 0.4375 — add it to the whole inches, then multiply by 2.54. On its own, 7/16" is 1.11 cm, or 11.11 mm.

How many cm is 6 feet?

182.88 cm. Six feet is 72 inches, and 72 × 2.54 = 182.88 — the conversion people most often need for height on a form that asks for centimeters.

How do I convert centimeters back to inches?

Divide by 2.54: 30.48 cm ÷ 2.54 = 12 in. Our mm to inches converter also gives you the nearest 1/16" reading, which is what you need when the answer has to be found on a tape.

Data sources: The conversion uses the inch as defined by the 1959 international yard and pound agreement — exactly 25.4 mm, hence exactly 2.54 cm. Every figure in the chart was produced by this page's converter using that factor and can be reproduced by entering the same inches. Related tools: mm to inches converter, kg to lbs converter, all math calculators.