Convert Centimeters to Inches
Convert centimeters (cm) to inches instantly, backed by the exact formula, worked examples, and the reference points worth memorizing.
- Millimeter (mm)10
- Centimeter (cm)1
- Meter (m)0.01
- Kilometer (km)0.00001
- Inch (in)0.393701
- Foot (ft)0.032808
- Yard (yd)0.010936
- Mile (mi)0.000006
- Ja/Chuk (자)0.033003
- Chi/Chon (치)0.330033
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The formula for cm to inches
One inch is defined internationally as exactly 2.54 cm, so you convert by dividing centimeters by 2.54. If you prefer to multiply, use 1 cm = 0.3937 inches. A 30 cm ruler is 30 ÷ 2.54 = 11.81 in, and 50 cm works out to 19.69 in. Because 2.54 is an exact definition, dividing introduces no rounding error, whereas 0.3937 is a truncated approximation. When you need real precision, divide by 2.54 rather than multiplying by the shorter factor.
When you actually need this
You reach for cm-to-inch conversion when reading clothing or shoe sizes from overseas stores, fitting photos and paper to US inch formats, or interpreting American blueprints and furniture specs. A height of 175 cm is 175 ÷ 2.54 = 68.9 in, which splits into 5 ft 8.9 in once you divide by 12. A4 paper (210 × 297 mm) is 8.27 × 11.69 in, and a 25 cm foot is about 9.84 in. Just remember that monitors and TVs are measured on the diagonal, so enter the diagonal, not the width.
Handy reference points and pitfalls
A few anchors cover most estimates: 2.54 cm = 1 inch, 30.48 cm = 1 foot (12 in), and 91.44 cm = 1 yard (36 in). It also helps to know that 100 cm is 39.37 in, so a meter is roughly 39.4 inches. US measurements often show inches as fractions like 1/8 or 1/16 rather than decimals, so 8.27 in reads as about 8 1/4 in. For woodworking or sewing where fractions matter, round your decimal result to the nearest common fraction.
Frequently asked questions
How many inches is exactly 1 cm?
One centimeter equals 0.393700787... inches, usually written as 0.3937 in. The cleaner definition runs the other way: 1 inch is exactly 2.54 cm, so dividing centimeters by 2.54 gives the most accurate result.
Why do multiplying by 0.3937 and dividing by 2.54 give slightly different answers?
Because 0.3937 is 1/2.54 truncated to four decimal places. Multiplying 100 cm by 0.3937 gives 39.37 in, while dividing by 2.54 gives 39.3701 in, and that tiny gap grows with larger numbers. Divide by 2.54 when precision counts.
How do I turn a height in cm into feet and inches?
Divide the centimeters by 2.54 to get total inches, then divide that by 12 — the whole number is feet and the remainder is inches. For example, 160 cm is 62.99 in, or 5 ft 3 in, and 180 cm is 70.87 in, or 5 ft 10.9 in.