Convert millimeters to centimeters
1 mm = 0.1 cm · Formula and table below. Converting the other way? Centimeters to Millimeters →
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Other units
- Meter (m) 0.001
- Kilometer (km) 0.000001
- Decimeter (dm) 0.01
- Centimeter (cm) 0.1
- Millimeter (mm) 1
- Micrometer (µm) 1000
- Nanometer (nm) 1,000,000
- Mile (mi) 6.213712×10⁻⁷
- Yard (yd) 0.001093613
- Foot (ft) 0.00328084
- Inch (in) 0.039370079
- Nautical mile (nmi) 5.399568×10⁻⁷
- Light year (ly) 1.057001×10⁻¹⁹
Reviewed on by the Skala Convert team
Ten millimeters make one centimeter.
How many millimeters are in a centimeter?
Ten. Millimeters to centimeters divides by 10, and centimeters to millimeters multiplies by 10. The millimeter figure is always the larger of the two, because the unit is smaller — if your answer shrank when converting to millimeters, you went the wrong way.
What does "mm of rain" mean?
One millimeter of rainfall means one liter of water fell on every square meter of ground. Rain is reported as depth rather than volume because depth is independent of area: a gauge the size of a bucket and a gauge the size of a field record the same number.
That makes the forecast easy to translate. A 50 mm storm drops 50 liters on every square meter — on a modest 100 m² roof, five metric tons of water heading for the gutters.
Why are technical drawings dimensioned in millimeters?
Because a single unit throughout removes ambiguity. The ISO 129-1 standard for technical product documentation lets a drawing state one predominant unit and leave it off every dimension; in mechanical engineering that unit is almost always the millimeter, so a bare 45 on a drawing means 45 mm. A drawing that quietly mixes units is a drawing that produces the wrong part.
What mistakes do people make converting mm to cm?
It is the easiest conversion on this site, which is exactly the problem. People do it in their heads without checking direction, and a factor-of-10 error on a machined part is not a rounding issue — it is scrap.
Who defines milli and centi?
The SI prefixes are set out in the SI Brochure published by the International Bureau of Weights and Measures (BIPM): milli is 10−3 and centi 10−2, so ten millimetres make a centimetre by definition. ISO 80000-1, the international standard on quantities and units, applies the same rules. On technical drawings, ISO 129-1 lets one predominant unit be stated once — in mechanical engineering, almost always the millimetre.
Formula
Centimeters = Millimeters × 0.1
10 mm = 1 cm
Conversion table
| mm | cm |
|---|---|
| 1 | 0.1 |
| 2 | 0.2 |
| 5 | 0.5 |
| 10 | 1 |
| 20 | 2 |
| 25 | 2.5 |
| 50 | 5 |
| 100 | 10 |
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Frequently asked questions
How many millimeters are in a centimeter?
Ten millimeters make one centimeter. Divide millimeters by 10 to get centimeters.
What does mm of rain mean?
One millimeter of rainfall means one liter of water fell on every square meter of ground. A 50 mm storm drops 50 liters per square meter.
Why are technical drawings in millimeters?
ISO 129-1 lets a drawing state one predominant unit and omit it from each dimension. In mechanical engineering that unit is almost always the millimeter, which keeps every number on the drawing in one consistent unit.