CM to Inches
Convert centimetres to inches instantly — 1 cm is 0.3937 inches. With a quick table and the divide-by-2.54 rule.
Fast, easy and free — your answer appears as you type, and whatever you enter stays on your device.
One centimetre is 0.3937 inches, so to convert centimetres to inches you divide by 2.54. Type any value below and the answer appears as you type — or scan the table for the common sizes.
How to use it
- Type the centimetre valueThe inch answer appears as you type — no button to press.
- Or go the other waySwap flips the direction to inch → centimetre in one tap.
- Check the workingThe exact factor or formula used is shown beneath the answer, so the result is checkable, not just asserted.
Common centimetre values in inches
| cm | in |
|---|---|
| 1 cm | 0.394 in |
| 2 cm | 0.787 in |
| 5 cm | 1.969 in |
| 10 cm | 3.937 in |
| 15 cm | 5.906 in |
| 20 cm | 7.874 in |
| 25 cm | 9.843 in |
| 30 cm | 11.81 in |
| 50 cm | 19.69 in |
| 100 cm | 39.37 in |
The quick rule for your head
Divide by 2.5 in your head and shave a little off: 30 cm ÷ 2.5 = 12, minus a touch ≈ 11.8 inches (exact: 11.81). For a faster rough cut, remember 10 cm ≈ 4 inches — so 25 cm is about 10 inches and 50 cm about 20. The error of the 2.5 shortcut is under 2%, tighter than most tape measures.
Where this conversion shows up
This is the screen-and-paper conversion: TV and laptop sizes are quoted in inches while furniture and rooms are measured in centimetres, so checking whether a 27-inch monitor fits a 70 cm shelf lands here. It is also constant in sewing and knitting, where US patterns speak inches and European ones centimetres.
Need other units too? The fulllength converter handles every pair and shows the exact factor behind each answer. For the opposite direction, use Inches to CM.
Questions people ask
How many inches is 1 cm?
0.3937 inches — just under four tenths of an inch. The exact relationship runs the other way: one inch is defined as exactly 2.54 cm, so centimetres to inches is a division by 2.54.
Is 30 cm exactly a foot?
No, close but not quite — a foot is 30.48 cm. A '30 cm ruler' is fractionally shorter than a foot-long one, which is why imperial rulers say 12 inches and metric ones stop at 30.
Why 2.54 exactly?
It is a definition, not a measurement: in 1959 the inch was fixed at exactly 25.4 mm internationally. Every cm-to-inch conversion since is exact arithmetic with no rounding in the factor itself.
How do I convert clothing sizes in cm to inches?
The same division by 2.54 — an 80 cm waist is 31.5 inches. Size labels round to the nearest whole inch, so expect a chart to say 31 or 32.