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Centimeters to Millimeters

Centimeters and Millimeters measure the same quantity in different unit systems. The relationship is 1 cm = 10 mm, which gives 10 mm per cm. Below you can convert any value, check a worked example and read the full chart.

Formula 1 cm = 10 mm

Need the other direction? Millimeters to Centimeters.

How to convert Centimeters to Millimeters

The centimetre is one hundredth of a metre and is common in clothing and furniture sizes. The millimetre is one thousandth of a metre and is the usual unit for engineering tolerances.

To convert Centimeters to Millimeters, multiply the value in cm by 10. For example, 10 cm × 10 = 100 mm. This works because the ratio between the two units is constant for every value in length.

Worked examples

cmmm
1 cm10 mm
2.5 cm25 mm
5 cm50 mm
10 cm100 mm
25 cm250 mm
50 cm500 mm
100 cm1,000 mm

Reverse conversion

mmcm
1 mm0.1 cm
5 mm0.5 cm
10 mm1 cm
25 mm2.5 cm
50 mm5 cm
100 mm10 cm

When this conversion is useful

This is the calculation you need when you are working across metric and imperial measurements, shopping abroad or reading a spec sheet. Because the factor is fixed, you can use the same number for a single measurement or for a batch: 1,000 cm is 10,000 mm.

Is the conversion exact?

Yes for practical use: the factors come from international definitions, with rounding applied only for display.

Reference: BIPM SI Brochure and NIST SP 811. Last reviewed: 2026-11-01.

cm to mm conversion chart

The chart lists the most requested values. For a value that is not here, use the converter at the top of the page.

Centimeters (cm)Millimeters (mm)
1 cm10 mm
2 cm20 mm
3 cm30 mm
4 cm40 mm
5 cm50 mm
6 cm60 mm
7 cm70 mm
8 cm80 mm
9 cm90 mm
10 cm100 mm
11 cm110 mm
12 cm120 mm
13 cm130 mm
14 cm140 mm
15 cm150 mm
16 cm160 mm
17 cm170 mm
18 cm180 mm
19 cm190 mm
20 cm200 mm
21 cm210 mm
22 cm220 mm
23 cm230 mm
24 cm240 mm
25 cm250 mm
26 cm260 mm
27 cm270 mm
28 cm280 mm
29 cm290 mm
30 cm300 mm
31 cm310 mm
32 cm320 mm
33 cm330 mm
34 cm340 mm
35 cm350 mm
36 cm360 mm
37 cm370 mm
38 cm380 mm
39 cm390 mm
40 cm400 mm
41 cm410 mm
42 cm420 mm
43 cm430 mm
44 cm440 mm
45 cm450 mm
46 cm460 mm
47 cm470 mm
48 cm480 mm
49 cm490 mm
50 cm500 mm
60 cm600 mm
70 cm700 mm
80 cm800 mm
90 cm900 mm
100 cm1,000 mm

Frequently asked questions

How many Millimeters are in 1 Centimeters?

1 cm equals 10 mm.

How do I convert Centimeters to Millimeters?

Multiply the cm value by 10. Example: 25 cm = 250 mm.

What is 2.5 cm in mm?

2.5 cm = 25 mm.

Is the cm to mm conversion exact?

Yes for practical use: the factors come from international definitions, with rounding applied only for display.

Does the calculator work offline?

Yes. The conversion runs in your browser with JavaScript, so it works after the page has loaded, even without a connection.

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