mm to cm Converter

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Convert millimeters to centimeters with the simple SI relation 1 cm = 10 mm, so 1 mm = 0.1 cm. Used for fine-resolution measurements such as paper thickness (typical office paper is 0.1 mm = 0.01 cm), wire gauge diameter, aquarium gravel grain size and packaging thickness. Browser-local conversion, no upload.

Millimeter (mm)
Centimeter (cm)

Millimeter (mm) → Centimeter (cm)

Quick reference table

Millimeter (mm)Centimeter (cm)
1 mm0.1 cm
2 mm0.2 cm
5 mm0.5 cm
10 mm1 cm
25 mm2.5 cm
50 mm5 cm
100 mm10 cm

Glossary

Millimeter (mm)

A millimeter is one thousandth of a meter (1 mm = 0.1 cm = 0.03937 inch). It is the default fine-resolution unit on rulers, mechanical drawings, electronics PCBs and rainfall gauges. Ten millimeters make a centimeter; one inch contains exactly 25.4 millimeters by international agreement since 1959.

Centimeter (cm)

A centimeter is one hundredth of a meter (1 cm = 10 mm = 0.3937 inch). It is the everyday metric unit for clothing sizes, body measurements, paper formats and small object dimensions. Two and a half centimeters approximate one inch; ninety-one centimeters approximate one yard.

Metric system (SI)

The metric system is a decimal system of measurement built around the meter for length, the kilogram for mass and the second for time, with multiples and submultiples expressed as powers of ten (millimeter, centimeter, kilometer). Adopted in France in 1799 and codified internationally as the International System of Units (SI) in 1960, it is now the official measurement system in nearly every country and the standard in science and engineering worldwide.

Imperial / US Customary system

The imperial system is the historical English system of weights and measures whose length units are the inch, foot, yard and mile (12 in = 1 ft, 3 ft = 1 yd, 1,760 yd = 1 mi). Codified by the British Weights and Measures Act of 1824 and aligned with US Customary by the international yard-and-pound agreement of 1959 (1 inch = 25.4 mm exactly), it is still used in the United States, the United Kingdom and a handful of other countries for everyday distances.

Related tools

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