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Centimeters to millimeters (cm to mm)

Type a value in centimeters and get the result in millimeters instantly — with the exact factor, a step-by-step formula and a table of common values.

Sources: NIST — Guide to the SI, Appendix B.8 (conversion factors: inch, foot, yard, mile)

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How to convert centimeters to millimeters

1 cm = 10 mm
1 mm = 0.1 cm

To convert centimeters to millimeters, multiply the value by 10.

Example: 10 cm × 10 = 100 mm.

Centimeters to millimeters conversion table

Centimeters (cm)Millimeters (mm)
0.11
0.55
110
220
550
10100
15150
20200
50500
1001,000

Related conversions

Centimeters to millimeters is a pure decimal shift — 1 cm is exactly 10 mm — but it still trips people up when a spec sheet, print template or workshop drawing mixes the two without saying so. A 10 cm measurement is 100 mm; a 0.5 cm tolerance is 5 mm. Because both units are metric, this conversion never involves rounding: you’re just moving a decimal point one place.

The pair matters most in contexts where millimeter precision is the working standard even though centimeters are the everyday unit — print and packaging design, PCB and small-parts manufacturing, and any technical drawing where a stated tolerance in millimeters needs converting back to the centimeters someone is measuring with a ruler or tape.

Because the conversion is exact and mechanical, the main risk isn’t the math — it’s misplacing the decimal point when switching between the two units under time pressure, which is exactly what this calculator eliminates.

FAQ

How many millimeters are in 10 cm?

10 cm is 100 mm. The conversion is exact: multiply centimeters by 10 to get millimeters, since both are metric units defined relative to the meter.

Why do some drawings use millimeters and others centimeters for the same kind of measurement?

It usually comes down to convention within an industry: engineering and manufacturing drawings favor millimeters because it avoids decimals for small parts, while general-purpose or consumer measurements often default to centimeters as the more intuitive everyday scale. Neither is more “correct” — they’re just different working conventions.

Is there ever a rounding error converting cm to mm?

No. Both centimeters and millimeters are exact decimal fractions of the meter (1 cm = 0.01 m, 1 mm = 0.001 m), so converting between them is exact multiplication or division by 10 with no measurement uncertainty introduced.

What’s the quickest mental shortcut for cm to mm?

Move the decimal point one place to the right — 12.5 cm becomes 125 mm. It works every time because the factor is a clean power of ten, unlike conversions to inches or feet.

Sources