CM to Inches Converter
Free cm to inches converter — divide by the exact factor 2.54 to turn centimetres into inches instantly, both directions, no signup.
About the CM to Inches Converter
Convert centimetres to inches with the exact international factor: 1 inch = 2.54 cm, so inches = cm ÷ 2.54. Type a value in either field — centimetres or inches — and the other updates instantly, with results shown to four decimal places and a copy button for the full line.
Screen sizes, waist measurements, paper formats, bike frames and picture frames are commonly quoted in inches, while rulers and tape measures across most of the world read in centimetres. Typical checks: 30 cm is 11.81 inches (just under a foot), 50 cm is 19.69 inches, and an 80 cm waist is 31.5 inches.
Because 2.54 is an exact defined value — not a rounded one — every result here is mathematically exact, making the tool safe for sewing patterns, woodworking plans and technical drawings where accumulated rounding errors matter.
How to Use the CM to Inches Converter
- 1Type a length in centimetres — for example 30.
- 2Read the inches result instantly (30 cm = 11.811 in).
- 3Edit the inches field to convert inches back to centimetres.
- 4Copy the result or use the reference table for common values.
Frequently Asked Questions
How many inches is 30 cm?
30 cm is 11.811 inches — just short of one foot (12 in = 30.48 cm). The calculation is 30 ÷ 2.54 = 11.811.
What is 1 cm in inches?
1 cm equals 0.3937 inches, or roughly 2/5 of an inch. Going the other way, 1 inch is exactly 2.54 cm.
What is 50 cm in inches?
50 cm is 19.685 inches, just under 20 inches. Similarly, 100 cm (1 metre) is 39.37 inches and 25 cm is 9.84 inches.
How do I convert cm to inches without a calculator?
Divide by 2.54, or for a quick estimate multiply the centimetres by 0.4: 30 cm × 0.4 = 12, close to the true 11.81 inches. For exact work always use the 2.54 factor this tool applies.
Why is the cm to inch factor exactly 2.54?
The 1959 international yard and pound agreement defined the inch as exactly 2.54 cm, ending small national differences between the US and UK inch. Every modern conversion, including this tool, uses that exact value.