Millimeters to Centimeters Converter
Enter the length in millimeters below to convert it to centimeters.
Convert Millimeters to Centimeters
Enter a value in millimeters (mm) to convert to centimeters (cm).
Millimeters to Centimeters Conversion Chart (1–40 Continuous)
Continuous 1 to 40 millimeters lookup table with exact decimals and reduced nearest 1/64 fractions. Highlighted rows mark common shop and ruler values.
| Millimeters (mm) | Decimal (cm) | Fraction — Nearest 1/64 (Reduced) | Nearest 1/16 (Tape) |
|---|---|---|---|
1 mm★ Common | 0.1 cm | 3/32 cm | 1/8 cm |
2 mm★ Common | 0.2 cm | 13/64 cm | 3/16 cm |
3 mm★ Common | 0.3 cm | 19/64 cm | 5/16 cm |
4 mm | 0.4 cm | 13/32 cm | 3/8 cm |
5 mm★ Common | 0.5 cm | 1/2 cm | 1/2 cm |
6 mm★ Common | 0.6 cm | 19/32 cm | 5/8 cm |
7 mm | 0.7 cm | 45/64 cm | 11/16 cm |
8 mm★ Common | 0.8 cm | 51/64 cm | 13/16 cm |
9 mm | 0.9 cm | 29/32 cm | 7/8 cm |
10 mm★ Common | 1 cm | 1 cm | 1 cm |
11 mm | 1.1 cm | 1 3/32 cm | 1 1/8 cm |
12 mm★ Common | 1.2 cm | 1 13/64 cm | 1 3/16 cm |
How to Convert Millimeters to Centimeters
To convert millimeters to centimeters, multiply the length by the following conversion ratio: 0.1 centimeters/millimeter.
Since one millimeter is equal to 0.1 centimeters, you can use this simple formula to convert:
The length in centimeters is equal to the length in millimeters multiplied by 0.1.
For example, here's how to convert 150 millimeters to centimeters using the formula above.
How Many Centimeters Are in a Millimeter?
There are 0.1 centimeters in a millimeter, which is why we use this value in the formula above.
Our millimeter fraction and decimal calculator can convert millimeters and centimeters, and it automatically converts the results to US customary, imperial, and SI metric values.
Millimeters and centimeters are both units used to measure length. Keep reading to learn more about each unit.
How to Convert Millimeters to Fractional Inches (1/16″, 1/32″ & 1/64″)
Plain-language method for turning decimal inches into a standard tape-measure or machinist ruler fraction
Calculators give you a decimal number (such as 5.905512 in), but tape measures and woodworking rulers are marked in binary fractions of an inch—most commonly 1/16″ on carpenter tapes, 1/32″ on fine woodworking rules, and 1/64″ on machinist scales.
Here is the step-by-step worked example for converting 150 millimeters (mm) into fractional inches:
- Find the decimal inches result: Convert 150 mm to inches to get 5.905512 in.
- Separate the whole inches from the decimal part: Keep the whole number 5 aside, leaving the decimal remainder 0.905512.
- Multiply the decimal part by your desired fraction denominator (16, 32, or 64) and round half up: Multiply 0.905512 by 16, 32, or 64, then round to the nearest whole number (values ending in .5 round up).
- Reduce the fraction to lowest terms: If the rounded top number (numerator) is even, divide both top and bottom by 2 (or their Greatest Common Divisor) until the top number is odd, then combine with your whole inches.
What Is a Millimeter?
A millimeter is a metric unit of length equal to one-thousandth (1/1,000) of a meter or one-tenth (1/10) of a centimeter. By international definition, there are exactly 25.4 millimeters in one inch. [1]
The millimeter, or millimetre, is a standard SI metric unit of length. Millimeters can be abbreviated as mm; for example, 1 millimeter can be written as 1 mm.
In the metric system, "milli" is the prefix for thousandths, or 10⁻³. Millimeters are the default unit on mechanical engineering drawings and architectural blueprints worldwide.
Millimeters are commonly measured using metric steel rules, digital vernier calipers, depth gauges, and micrometers in CNC machining, 3D printing, automotive fasteners, and precision manufacturing.
What Is a Centimeter?
A centimeter is a metric unit of length equal to one-hundredth (1/100) of a meter, which is the International System of Units (SI) base unit of length. One centimeter is also equal to 10 millimeters or approximately 0.39370079 inches. [2]
The centimeter, or centimetre, is part of the SI metric system used worldwide for everyday, scientific, and clinical measurements. Centimeters can be abbreviated as cm; for example, 1 centimeter can be written as 1 cm.
In the metric system, "centi" is the Latin-derived prefix for hundredths, or 10⁻². Because 1 international inch is legally defined as 2.54 centimeters, converting between centimeters and inches is anchored by an exact mathematical constant.
Centimeters are measured using metric rulers, tailor's measuring tapes, stadiometers (for human height), and vernier calipers across carpentry, apparel sizing, school science, and medical charts.
When converting length between millimeters (mm) and centimeters (cm), keep full floating-point precision (1 mm = 0.1 cm; 1 cm = 10 mm) during intermediate calculations and round only the final centimeter figure to match your instrument tolerance.
More Millimeter & Centimeter Conversions
Need to calculate in the opposite direction? Use our centimeters to millimeters converter (cm to mm) to switch your starting unit immediately. You can also explore related tools such as converting inches to centimeters, converting feet to centimeters, or converting millimeters to inches.
Convert from Millimeters
Frequently Asked Questions
References
- [1]NIST OWM StandardNIST OWM (SI Units — Length)·Length Metrology Standard — Millimeters (mm) to Centimeters (cm)
- [2]BIPM SpecificationBIPM (SI Base Unit: Metre (m))·Unit Specifications: Millimeter (mm) & Centimeter (cm)
- [3]NIST HB 133 ReferenceNIST HB 133 (NIST Handbook 133 (2019 Ed.))·Conversion Factors & Mathematical Basis (mm to cm)