Convert Centimeters to Millimeters
1 centimeter is 10 mm. One centimeter is exactly 10 millimeters.
One centimeter is 10 millimeters. To convert centimeters to millimeters, multiply by 10; to go the other way, divide by 10 or multiply by 0.1. The factor is exact rather than rounded: it follows from NIST. One hundredth of a meter, and the unit most of the world states height in.
Factor checked against the defining standard · How we check
- Centimeters × 10
1 * 1010 mm
1 centimeter in every length unit
| Unit | Value | Exact factor |
|---|---|---|
| inches | 0.3937007874 in | × 0.393700787402 |
| feet | 0.03280839895 ft | × 0.0328083989501 |
| yards | 0.01093613298 yd | × 0.0109361329834 |
| miles | 0.000006213711922 mi | × 0.00000621371192237 |
| millimeters | 10 mm | × 10 |
| decimetres | 0.1 dm | × 0.1 |
| centimeters (as entered) | 1 cm | — |
| meters | 0.01 m | × 0.01 |
| kilometers | 0.00001 km | × 0.00001 |
| nautical miles | 0.000005399568035 nmi | × 0.00000539956803456 |
| micrometers | 10,000 µm | × 10,000 |
| nanometers | 10,000,000 nm | × 10,000,000 |
| thou | 393.7007874 thou | × 393.700787402 |
Factors are entered by hand from NIST rather than derived from a units library, so the ones that terminate are exact rather than rounded.
The same converter answers this pair however it is written: centimetres to millimetres is the British spelling of the same units — the metre and the litre are spelled that way outside the United States and the quantity does not change.
How do you convert centimeters to millimeters? The converter and the working
- 1.Take the measurement in centimeters.
- 2.Multiply by 10 — that is how many millimeters fit in one centimeter.
- 3.To go back the other way, divide by 10, or multiply by 0.1.
Worked example: 25 centimeters to millimeters
- Formula
- cm × 10 = mm
- Arithmetic
- 25 × 10 = 250 mm
- Answer
- 25 cm = 250 mm
The factor is exact, so this figure is exact too — only the display is rounded.
Centimeters to millimeters conversion table
| Centimeters | Millimeters |
|---|---|
| 1 cm | 10 mm |
| 2 cm | 20 mm |
| 3 cm | 30 mm |
| 4 cm | 40 mm |
| 5 cm | 50 mm |
| 6 cm | 60 mm |
| 7 cm | 70 mm |
| 8 cm | 80 mm |
| 9 cm | 90 mm |
| 10 cm | 100 mm |
| 12 cm | 120 mm |
| 15 cm | 150 mm |
| 20 cm | 200 mm |
| 25 cm | 250 mm |
| 50 cm | 500 mm |
| 100 cm | 1,000 mm |
| 200 cm | 2,000 mm |
| 300 cm | 3,000 mm |
| 500 cm | 5,000 mm |
| 1000 cm | 10,000 mm |
| 2000 cm | 20,000 mm |
| 5000 cm | 50,000 mm |
| 10000 cm | 100,000 mm |
What is a centimeter?
One hundredth of a meter, and the unit most of the world states height in.
What is a millimeter?
One thousandth of a meter. The working unit of metric engineering drawings, which avoid decimals by using it throughout.
How many millimeters are in a centimeter?
One centimeter is 10 millimeters, exactly. Going the other way, one millimeter is 0.1 centimeters. Both figures come from the same defined relation rather than from a measurement, which is why they are the same today as they were in 1959.
Every length unit here
The whole group — 13 units with their symbols and the size of each one in meters — is on the conversion index, along with every pair it makes. The table above already gives each of them relative to a centimeter.
Source: NIST — international yard and pound agreement (inch = 25.4 mm exactly)
Cite this page
- APA
- Rule Calculator. (2026). Convert Centimeters to millimeters. Rule Calculator. https://rulecalculators.com/convert/centimeter-to-millimeter
- MLA
- "Convert Centimeters to millimeters." Rule Calculator, August 16, 2026, https://rulecalculators.com/convert/centimeter-to-millimeter.
- Chicago
- Rule Calculator. "Convert Centimeters to millimeters." Rule Calculator. Last reviewed August 16, 2026. https://rulecalculators.com/convert/centimeter-to-millimeter.
The date is when the figures on this page were last checked against their source, not the day you opened it. Add your own access date if your style needs one.
Questions people actually ask
- How many millimeters are in a centimeter?
- 10. One thousandth of a meter. The working unit of metric engineering drawings, which avoid decimals by using it throughout.
- How do I convert millimeters back to centimeters?
- Divide by 10, or multiply by 0.1 — they are the same operation.
Other length conversions
Millimeters to centimeters — the same conversion the other way.