Length / cm → mm
Convert Centimeters to Millimeters
From a small measurement to a long distance. Move between metric and imperial units. Convert Centimeters (cm) to Millimeters (mm). Find the formula, worked examples, unit definitions, and practical guidance below.
Reverse: Millimeters to Centimeters →
How to convert centimeters to millimeters
Length conversion changes the unit of a distance. Area and volume need squared and cubed factors; this calculator does not convert square feet or cubic feet.
Use x for the value in cm, b for the intermediate value in m, and y for the result in mm.
mm = cm × 0.01 ÷ 0.001
Worked examples
10 cm ≈ 100 mm
Step 1: (10 × 0.01) ≈ 0.1 m.
Step 2: 0.1 ÷ 0.001 ≈ 100 mm.20 cm ≈ 200 mm
Step 1: (20 × 0.01) ≈ 0.2 m.
Step 2: 0.2 ÷ 0.001 ≈ 200 mm.
Results are rounded to 12 significant digits. Converting units does not increase the precision of the original measurement. Very large or small values outside JavaScript’s finite numeric range are rejected.
About Centimeters
A centimeter is one hundredth of a meter. It is often used for body measurements, product dimensions, and clothing sizes.
About Millimeters
A millimeter is one thousandth of a meter. Small dimensions and engineering drawings often use millimeters; retain the precision of the original measurement.
Definitions and sources
Use consistent length units when carrying dimensions into construction calculations.
Centimeters to millimeters reference table
| Centimeters (cm) | Millimeters (mm) |
|---|---|
| 1 | 10 |
| 5 | 50 |
| 10 | 100 |
| 25 | 250 |
| 50 | 500 |
| 100 | 1000 |
| 1000 | 10000 |
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