Centimetres to millimetres
Multiply centimetres by 10 to get millimetres.
5 cm = 50 mm
How to convert centimetres to millimetres
The millimetre is one thousandth of a metre (10⁻³ m). The centimetre is one hundredth of a metre (10⁻² m).
Worked example — 5 cm: 5 × 10 = 50 mm.
Centimetres to millimetres table
| Centimetres | Millimetres |
|---|---|
| 0.5 cm | 5 mm |
| 1 cm | 10 mm |
| 2 cm | 20 mm |
| 3 cm | 30 mm |
| 5 cm | 50 mm |
| 10 cm | 100 mm |
| 20 cm | 200 mm |
| 50 cm | 500 mm |
| 100 cm | 1,000 mm |
Reverse and related
About centimetres and millimetres
Centimetre (cm)
1 cm = 10 mmDefinition. One hundredth of a metre (10⁻² m)
History and origin
The centimetre is one hundredth of a metre, part of the decimal metric system introduced in France in the 1790s. It was the base length of the older centimetre-gram-second system before the metre-kilogram-second system prevailed.
Current use
Centimetres are the everyday metric unit for body height, paper and screen sizes, and clothing measurements.
Source: BIPM, The International System of Units (SI), 9th ed. (2019)
Millimetre (mm)
1 mm = 0.1 cmDefinition. One thousandth of a metre (10⁻³ m)
History and origin
The millimetre is one thousandth of a metre, defined with the rest of the decimal metric system in the 1790s. Its small size suits precise work.
Current use
Millimetres are used for rainfall, engineering tolerances, and the sizes of screws, hardware and printed parts.
Source: BIPM, The International System of Units (SI), 9th ed. (2019)
Where people use this
Centimetres: height, paper and screen sizes, clothing measurements. Millimetres: rainfall, engineering tolerances, screws and hardware. 1 cm is exactly 10 mm.
Every value is carried to full double precision; the display is rounded.
Both units are defined in BIPM, The International System of Units (SI), 9th ed. (2019).
Questions people ask
How many mm are in a cm?
One centimetre is exactly 10 millimetres.
How many mm is 5 cm?
5 cm is 50 mm.
What is 2.5 cm in mm?
2.5 cm is 25 mm.