Centimetres to Millimetres
Type a value in Centimetres and get the result in Millimetres, calculated exactly.
30 Centimetres = 300 Millimetres
Precision
Exact factorThis result is exact.
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Formula
mm = cm × 10
To convert Centimetres to Millimetres, multiply the value by 10.
Worked examples
- 1 cm × 10 = 10 mm
- 30 cm × 10 = 300 mm
- 100 cm × 10 = 1,000 mm
This factor is exact by definition.
Conversion table
| Centimetres (cm) | Millimetres (mm) |
|---|---|
| 1 | 10 |
| 2 | 20 |
| 3 | 30 |
| 4 | 40 |
| 5 | 50 |
| 6 | 60 |
| 7 | 70 |
| 8 | 80 |
| 9 | 90 |
| 10 | 100 |
| 15 | 150 |
| 20 | 200 |
| 25 | 250 |
| 30 | 300 |
| 40 | 400 |
| 50 | 500 |
| 60 | 600 |
| 70 | 700 |
| 75 | 750 |
| 80 | 800 |
| 90 | 900 |
| 100 | 1,000 |
Values marked ≈ are rounded; the rest are exact.
Reverse table: Millimetres to Centimetres
| Millimetres (mm) | Centimetres (cm) |
|---|---|
| 1 | 0.1 |
| 2 | 0.2 |
| 3 | 0.3 |
| 4 | 0.4 |
| 5 | 0.5 |
| 6 | 0.6 |
| 7 | 0.7 |
| 8 | 0.8 |
| 9 | 0.9 |
| 10 | 1 |
| 15 | 1.5 |
| 20 | 2 |
| 25 | 2.5 |
| 30 | 3 |
| 40 | 4 |
| 50 | 5 |
| 60 | 6 |
| 70 | 7 |
| 75 | 7.5 |
| 80 | 8 |
| 90 | 9 |
| 100 | 10 |
Unit definitions
- Centimetres cm
- One hundredth of a metre.
- Millimetres mm
- One thousandth of a metre.
Questions people ask
Centimetres to Millimetres: what is the conversion factor?
One cm is 10 mm.
How do I convert Centimetres to Millimetres?
Use the formula above. For example, 30 cm = 300 mm.
Is the conversion exact?
Yes. Both units have exact definitions, so the factor is exact; a result is only rounded when its decimals never end.
Factors checked 19 October 2026.