MM to CM Calculator
Convert millimetres to centimetres instantly. Enter a value and get the exact conversion, plus bonus results in metres, inches, and feet.
Length Input
Enter a value to convert between millimetres and centimetres
Enter any positive or negative number of millimetres.
Your Conversion
Result plus equivalent metres, inches, and feet
Enter a value above and click Convert to see the result in centimetres and other common units.
Understanding MM to CM Conversion
Millimetres and centimetres are both metric units of length, related by a simple factor of 10, which makes converting between them straightforward.
mm to cm
Divide the millimetre value by 10. For example, 120mm ÷ 10 = 12cm.
cm to mm
Multiply the centimetre value by 10. For example, 8cm × 10 = 80mm.
Why Base 10?
The metric system is decimal, so every unit step (mm → cm → m) is a clean multiple of 10, avoiding messy fractions.
Common Uses
Millimetres are used for precise measurements like screws and paper thickness; centimetres are used for everyday items like books and screens.
MM to CM Conversion Chart
A quick lookup of common millimetre to centimetre conversions.
| Millimetres (mm) | Centimetres (cm) | Inches (approx.) | Common Reference |
|---|---|---|---|
| 1 mm | 0.1 cm | 0.039 in | Thickness of a credit card |
| 5 mm | 0.5 cm | 0.197 in | A small button |
| 10 mm | 1 cm | 0.394 in | Width of a pencil eraser |
| 25 mm | 2.5 cm | 0.984 in | Roughly 1 inch |
| 50 mm | 5 cm | 1.969 in | Width of a golf ball |
| 100 mm | 10 cm | 3.937 in | Length of a smartphone (short side) |
| 250 mm | 25 cm | 9.843 in | Length of an A4 sheet (approx.) |
| 1000 mm | 100 cm | 39.37 in | Equal to 1 metre |
MM to CM FAQ
Everything you need to know about converting between millimetres and centimetres.
To convert millimetres to centimetres, divide the millimetre value by 10. This is because there are 10 millimetres in every centimetre. For example, 50mm ÷ 10 = 5cm.
There are exactly 10 millimetres (mm) in 1 centimetre (cm). This is a fixed metric conversion, since both units are part of the base-10 metric system.
To convert centimetres to millimetres, multiply the centimetre value by 10. For example, 7cm × 10 = 70mm.
A millimetre (mm) is a smaller unit of length than a centimetre (cm). Both are part of the metric system, with 1 centimetre equal to 10 millimetres. Millimetres are typically used for very precise or small measurements, while centimetres are used for everyday lengths.
There are exactly 25.4 millimetres in 1 inch. This conversion factor is fixed by international agreement and is used to convert between metric and imperial measurements.
The metric system uses a base-10 (decimal) structure so that converting between units only requires multiplying or dividing by powers of 10, such as 10, 100, or 1000. This makes calculations simpler and more consistent than non-decimal systems like imperial units.