How to Convert Millimetres to Centimetres (mm to cm)
Length conversions come up when reading overseas furniture specs, cycling the Round Island Route in kilometres while a foreign app shows miles, or checking marine distances in the Singapore Strait in nautical miles. This guide shows how to convert millimetres into centimetres by hand, with examples and a quick-reference table.
The conversion
To convert millimetres to centimetres, multiply the value by 0.1. To go the other way, divide by the same number (or multiply by 10). For a quick estimate, multiply by about 0.1.
Centimetres = millimetres × 0.1
Worked examples
- 3 mm = 0.3 cm
- 12.5 mm = 1.25 cm
- 75 mm = 7.5 cm
Millimetres to Centimetres table
| Millimetres | Centimetres |
|---|---|
| 1 mm | 0.1 cm |
| 2 mm | 0.2 cm |
| 5 mm | 0.5 cm |
| 10 mm | 1 cm |
| 20 mm | 2 cm |
| 25 mm | 2.5 cm |
| 50 mm | 5 cm |
| 100 mm | 10 cm |
| 250 mm | 25 cm |
| 500 mm | 50 cm |
| 1,000 mm | 100 cm |
Common questions
Is mm to cm exact?
The factors used here are the internationally defined values where they exist; results are rounded for display only.
How do I convert back?
Use the Centimetres to Millimetres converter.
Mistakes to avoid
Rounding the factor too early
Using 3 instead of 3.28 for feet per metre introduces an error of almost 9% before you have started.
Dropping the units
A bare number without a unit is easy to misread later. Always write the unit with the result.
Mixing similar-sounding units
US and imperial gallons, pints and tons are different sizes, and decimal kilobytes differ from binary kibibytes.
Background
A conversion table is handy for common values, but a calculator is faster and avoids interpolation errors for anything in between.
Singapore adopted the metric system in the 1970s, replacing imperial units and traditional Chinese measures in most official uses. Metric units are now standard in schools, trade and government, but older units survive in property, markets and imported goods.
Writing the units next to every number while you work is the simplest way to avoid mistakes. If the units do not cancel to leave the one you want, the calculation is set up wrongly.
For any value, use the Millimetres to Centimetres Converter or browse all length converters.
Run your own numbers: Millimetres to Centimetres Converter