Cm to Mm

Convert Centimeters to Millimeters

"Cm to Mm" Calculator

Convert
cm
 to Millimeters

How to Convert cm to mm

Centimeters to Millimeters Conversion Formula

To convert cm to mm, multiply by 10:

millimeters = centimeters × 10

A centimeter is exactly one hundredth of a meter and a millimeter exactly one thousandth, so every centimeter holds 10 millimeters. The factor is a definition, not a measurement — the answer never needs rounding.

Step-by-Step: cm to mm

  1. Take the length in centimeters
  2. Multiply it by 10 — move the decimal point one place to the right
  3. Read the result in millimeters

Common cm to mm Conversions

Centimeters (cm)Millimeters (mm)
0.1 cm1 mm
0.2 cm2 mm
0.5 cm5 mm
1 cm10 mm
1.5 cm15 mm
2 cm20 mm
2.5 cm25 mm
3 cm30 mm
4 cm40 mm
5 cm50 mm
6 cm60 mm
6.5 cm65 mm
7 cm70 mm
8 cm80 mm
10 cm100 mm
12 cm120 mm
15 cm150 mm
20 cm200 mm
30 cm300 mm
50 cm500 mm
100 cm1,000 mm

Metric Length Units Table

Every metric length unit is ten times the next smaller one. One meter splits exactly into:

1 meter10 decimeters100 centimeters1,000 millimeters

Above the meter sits the kilometer: 1 km = 1,000 m. So 1 cm = 10 mm — the ten small divisions between two numbered marks on a ruler.

Practical Applications of cm to mm

  • DIY and hardware: Screws, drill bits and wall plugs are sold in millimeters, while you measured the job in centimeters
  • Engineering drawings: A sketch in centimeters has to become millimeters before it goes to a workshop or a laser cutter
  • 3D printing: Slicers and printer settings work in millimeters
  • Sewing: Seam allowances and buttons in millimeters next to pattern sizes in centimeters
  • School: Answers asked in millimeters when the exercise gives centimeters
  • Photography and optics: Lens focal lengths and sensor sizes are given in millimeters

History of the Centimeter and Millimeter

Both units were born with the metric system in revolutionary France in the 1790s. The meter was defined as one ten-millionth of the distance from the pole to the equator, and the prefixes centi- (a hundredth, from Latin centum) and milli- (a thousandth, from mille) produced the smaller units. Engineering settled on the millimeter as its working unit, while everyday life kept the centimeter; since 1983 the meter — and with it both units — is defined by the speed of light.

Mental Math: cm to mm

No calculator is needed: multiplying by 10 is moving the decimal point one place to the right. 0.8 cm → 8 mm; 2.5 cm → 25 mm; 13 cm → 130 mm; 45 cm → 450 mm. A whole number of centimeters just gains a zero.

See Also

About "Cm to Mm" Calculator

This converter turns centimeters into millimeters (cm to mm). One centimeter is exactly 10 millimeters, so the answer is the centimeter value multiplied by 10. For example, it can help you find out how many millimeters is 1 cm? (The answer is: 10). Enter the number of centimeters (e.g. '1') and hit the 'Convert' button.

FAQ

How many mm are in 1 cm?

There are exactly 10 millimeters in 1 centimeter (1 cm = 10 mm) — the ten small divisions between two numbered marks on a ruler.

What is the formula to convert cm to mm?

Multiply the centimeter value by 10 — that is, move the decimal point one place to the right. For example, 6.5 cm × 10 = 65 mm.

How many mm is 1.5 cm?

1.5 cm is exactly 15 mm (1.5 × 10 = 15).