Inches to Centimeters Converter
Type a value in either box and the other updates instantly, both ways.
12 in = 30.48 cm
This converter runs entirely in your browser. Nothing you type is uploaded.
How to use this tool
This inches to cm converter works in both directions, so you never have to clear a field before switching. Type a number of inches into the left box and the centimeters box fills in automatically. Type centimeters on the right and the inches box updates the same way. Use the Swap units button to flip the two boxes, Clear to start over, and Copy result to put the conversion on your clipboard. It is ideal for length sizing conversion when you are reading a product listing in one unit and need the other.
The formula
inches = centimeters ÷ 2.54
One inch is defined as exactly 2.54 centimeters, so converting in to centimeters is a single multiplication. Going the other way you divide by 2.54. Because the factor is exact, the conversion is not an approximation, only the rounding of the displayed result is. This tool keeps a few decimal places so you can use it for both rough estimates and precise measurements.
A real example
Say a TV is advertised as 55 inches across the diagonal and you want the size in centimeters. Multiply 55 by 2.54 to get 139.7 cm. To check the reverse, divide 139.7 by 2.54 and you land back on 55 inches. A 30 cm school ruler, by the same math, is 30 ÷ 2.54 = about 11.81 inches, which is why it is often labeled as 12 inches with a little spare length.
Inches to cm chart
This inches to cm chart covers common sizes so you can eyeball a value quickly without typing.
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Common questions
How many cm are in one inch?
Exactly 2.54 centimeters. The inch was officially defined as 2.54 cm in 1959, so the value is exact rather than rounded.
How do I convert in to centimeters by hand?
Multiply the number of inches by 2.54. For example, 8 inches is 8 × 2.54 = 20.32 cm. To go from cm back to inches, divide by 2.54 instead.
Why does the converter update both fields?
The two inputs are linked. Whichever box you type in is treated as the source, and the tool fills the other box for you, so you can do length sizing conversion in either direction without clearing anything.
How accurate is the result?
The math is exact because 1 inch equals exactly 2.54 cm. The only rounding is in how many decimal places are shown, which is enough for everyday clothing, screen, and furniture measurements.
What is 12 inches in centimeters?
12 inches equals 30.48 cm. That is one foot, which is why a standard foot ruler is just over 30 cm long.