Convert CM to MM, Free
Type any CM value and see the MM result instantly. No button press needed.
How to convert CM to MM
Centimeters and millimeters are both metric units in the same base-10 system, so converting between them is a simple multiplication or division by 10. One centimeter equals exactly 10 millimeters. Despite the simplicity, it is easy to misplace a decimal point when you are working from a spec sheet or blueprint, which is exactly where a quick inline converter removes doubt.
The calculation is instant and runs locally in your browser. Type the centimeter value and the millimeter equivalent appears right away, no server request involved.
Enter the centimeter value
Type your measurement in centimeters into the input field. Decimals work, so 3.5 cm is perfectly valid.
Read the millimeter result
The millimeter value appears immediately. 3.5 cm = 35 mm.
Copy the result
Highlight the output and copy it to your drawing, spec sheet, or cutting plan.
Convert in the opposite direction
Switch to mm to cm if you are starting from a millimeter measurement and need centimeters.
Frequently asked questions
How many millimeters in a centimeter?
Exactly 10 millimeters. 1 cm = 10 mm, so to convert cm to mm multiply by 10.
When would I need millimeters instead of centimeters?
Engineering drawings, woodworking, metalworking, jewelry making, and most technical specs use millimeters because centimeters introduce unnecessary decimal places for small dimensions.
How do I convert 15 cm to mm?
15 x 10 = 150 mm. It is always a clean multiplication by 10 in either direction.
What about converting cm to meters?
Divide by 100. 15 cm = 0.15 m. Use a separate cm-to-meters converter if you need that direction.