Converting millimeters to centimeters is one of the simplest conversions in the metric system — and one of the most frequently needed. The millimeter (mm) is the precision unit of everyday metric measurement: engineering drawings, 3D printing, jewellery, and electronics all work in millimeters. The centimeter (cm) is its larger sibling, the unit of rulers, clothing sizes, and product dimensions. Because ten millimeters make exactly one centimeter, the conversion is a single shift of the decimal point.
The metric system’s base-10 design is what makes this conversion trivial: going from millimeters to centimeters just divides by 10. A 45 mm watch case is 4.5 cm across; a 120 mm paperback width is 12 cm. Students meet this conversion early in science lessons, and makers switching between caliper readings in millimeters and printed plans in centimeters use it constantly. Because the factor is exact, there is never any rounding error — only as many decimal places as you choose to display.
Quick reference for common values: a standard pencil is about 7 mm thick (0.7 cm), a credit card is 85.6 mm long (8.56 cm), and an AA battery measures 50.5 mm (5.05 cm) in length. Because the conversion is just a shift of the decimal point, you can do it mentally — but the calculator above removes all doubt for precise work. Digital calipers typically read to 0.01 mm, which is 0.001 cm — a reminder of why the millimeter remains the precision unit of choice in workshops.
Mm to Cm Converter
Result will appear here
Mm to Cm Conversion Formula
The conversion formula is: cm = mm ÷ 10
Worked example: 25 mm ÷ 10 = 2.5 cm — so a 25-millimeter bolt is exactly two and a half centimeters long.
To convert back, multiply instead of dividing: mm = cm × 10.
How to Convert Mm to Cm
- Enter your value in millimeters in the converter above.
- The result in centimeters appears instantly as you type.
- Use the Swap button to convert centimeters back to millimeters.
- For manual calculations, divide the millimeter value by 10.
Mm to Cm Conversion Chart
| Millimeters (mm) | Centimeters (cm) |
| 1 | 0.1 |
| 2 | 0.2 |
| 3 | 0.3 |
| 4 | 0.4 |
| 5 | 0.5 |
| 6 | 0.6 |
| 7 | 0.7 |
| 8 | 0.8 |
| 9 | 0.9 |
| 10 | 1 |
| 25 | 2.5 |
| 50 | 5 |
| 100 | 10 |
FAQs
What is the formula to convert millimeters to centimeters?
Divide millimeters by 10: centimeters = millimeters ÷ 10. For example, 80 mm ÷ 10 = 8 cm. It is the simplest metric conversion because the factor is a clean power of ten.
How many centimeters are in 10 millimeters?
Ten millimeters equal exactly one centimeter. This 10:1 relationship is the foundation of the whole conversion — every centimeter on a ruler is divided into ten millimeter marks.
How many millimeters are in 1 centimeter?
There are exactly 10 millimeters in one centimeter. This follows directly from the metric definition of the centimeter as one hundredth of a meter and the millimeter as one thousandth.
Which is bigger, a millimeter or a centimeter?
A centimeter is ten times bigger than a millimeter. On a standard ruler, the numbered marks are centimeters, and the ten small divisions between each pair of numbers are millimeters.
How do I convert centimeters back to millimeters?
Multiply the centimeters by 10. The Swap button on the converter above reverses the calculation instantly, so a 7.5 cm measurement becomes 75 mm with one click.