Centimeters to Millimeters Calculator

Metric length converter

Convert centimeters and millimeters

Switch direction without choosing from a long unit list. Centimeters and millimeters are SI decimal units, so the conversion factor is exactly 10.

Result

1 cm = 10 mm

Conversion factor1 cm = 10 mm

Formula usedmillimeters = centimeters × 10

Why the factor is exact

One metric step, no estimated ratio

The SI prefix centi means 10⁻² and milli means 10⁻³. One centimeter is therefore exactly ten millimeters: 1 cm = 10 mm.

1
Start with the entered length
Example: 5 cm.
2
Apply the direction formula
5 × 10 = 50.
3
Write the target unit
5 cm = 50 mm.

Quick reference

Centimeters to Millimeters conversion table

Common cm values converted to mm
Centimeters (cm)	Millimeters (mm)
0.1 cm	1 mm
0.2 cm	2 mm
0.3 cm	3 mm
0.4 cm	4 mm
0.5 cm	5 mm
0.6 cm	6 mm
0.7 cm	7 mm
0.8 cm	8 mm
0.9 cm	9 mm
1 cm	10 mm
2 cm	20 mm
5 cm	50 mm
10 cm	100 mm
25 cm	250 mm
50 cm	500 mm
100 cm	1,000 mm

Fine layout and fabrication

Turn centimetre dimensions into millimetre marks

Centimetres are convenient for describing an object; millimetres are often better for cut lines, product drawings, and tolerances. The factor of ten is exact, while the object and measuring method remain imperfect.

Side-by-side guide · Fine layout and fabrication

Length factors do not transfer unchanged to powers

Direct operation: millimetres = centimetres × 10
Exact relationship: 1 cm = 10 mm
Example: 8.5 cm = 85 mm

Linear dimension
Multiply centimetres by 10 to obtain millimetres.
Area
One square centimetre is 100 square millimetres because both axes scale by ten. Use the area calculator to combine dimensions instead of treating a surface as one length.
Volume
One cubic centimetre is 1,000 cubic millimetres. The exponent on the unit determines the exponent on the scale factor.

Turn centimetre dimensions into millimetre marks: Centimetres are convenient for describing an object; millimetres are often better for cut lines, product drawings, and tolerances. The factor of ten is exact, while the object and measuring method remain imperfect.

Subdivide a centimetre without changing the length

Centi represents 10⁻² of a metre and milli represents 10⁻³. Moving from centimetres to millimetres therefore multiplies the numerical value by ten. A width of 8.5 cm becomes 85 mm, 2.54 cm becomes 25.4 mm, and 0.06 cm becomes 0.6 mm.

This direction suits craft layouts, model dimensions, hardware clearances, packaging dielines, and manufacturing notes where a millimetre-based scale is easier to mark. It is not evidence that the source was measured to the nearest millimetre. The conversion only expresses the same declared length in a smaller unit.

Use the smaller unit to remove ambiguous decimal placement

A good millimetre cut list makes each number's role visible.

Convert each linear dimension independently and write the mm symbol after every value rather than relying on a heading that may be separated from the data.
Convert the tolerance too: 8.5 ± 0.02 cm becomes 85 ± 0.2 mm, preserving the same allowable physical range.
Keep nominal sizes separate from measured sizes. A marketed 10 cm part may not measure exactly 100 mm.
Do not add plural letters to unit symbols. Write 85 mm, not 85 mms, and leave a space between the number and symbol.

Length factors do not transfer unchanged to powers

Linear dimension

Multiply centimetres by 10 to obtain millimetres.

Area

One square centimetre is 100 square millimetres because both axes scale by ten. Use the area calculator to combine dimensions instead of treating a surface as one length.

Volume

One cubic centimetre is 1,000 cubic millimetres. The exponent on the unit determines the exponent on the scale factor.

Stay metric or cross systems for a stated reason

When millimetre specifications need a shorter customer-facing number, use the millimetres-to-centimetres calculator. If the dimension belongs in a room-scale report, the centimetres-to-metres calculator moves in the other direction along the SI ladder.

Only cross to customary units when the receiving drawing or hardware system requires it. The millimetres-to-inches calculator explains exact decimal inches versus nearby shop fractions, while the feet-and-inches workbench handles mixed construction notation. A conversion cannot choose a drill, tolerance class, or manufacturing fit on the user's behalf.

Important limitations

The calculator converts mathematical length values only. It does not account for instrument resolution, manufacturing tolerance, significant-figure policy, or measurement uncertainty.

Review the stated scope, calculation method, assumptions, supported inputs, and effective dates, and obtain qualified advice before using a high-stakes result.

This formula passed its registered engineering tests and is published under an explicit site-owner policy authorization. No independent expert, QA, editorial, legal, or third-party review is claimed. Verify consequential results with a qualified professional.

Fine layout and fabrication

Turn centimetre dimensions into millimetre marks

Side-by-side guide · Fine layout and fabrication

Length factors do not transfer unchanged to powers

Direct operation: millimetres = centimetres × 10
Exact relationship: 1 cm = 10 mm
Example: 8.5 cm = 85 mm

Linear dimension
Multiply centimetres by 10 to obtain millimetres.
Area
One square centimetre is 100 square millimetres because both axes scale by ten. Use the area calculator to combine dimensions instead of treating a surface as one length.
Volume
One cubic centimetre is 1,000 cubic millimetres. The exponent on the unit determines the exponent on the scale factor.

Subdivide a centimetre without changing the length

Use the smaller unit to remove ambiguous decimal placement

A good millimetre cut list makes each number's role visible.

Convert each linear dimension independently and write the mm symbol after every value rather than relying on a heading that may be separated from the data.
Convert the tolerance too: 8.5 ± 0.02 cm becomes 85 ± 0.2 mm, preserving the same allowable physical range.
Keep nominal sizes separate from measured sizes. A marketed 10 cm part may not measure exactly 100 mm.
Do not add plural letters to unit symbols. Write 85 mm, not 85 mms, and leave a space between the number and symbol.

Length factors do not transfer unchanged to powers

Linear dimension

Multiply centimetres by 10 to obtain millimetres.

Area

One square centimetre is 100 square millimetres because both axes scale by ten. Use the area calculator to combine dimensions instead of treating a surface as one length.

Volume

One cubic centimetre is 1,000 cubic millimetres. The exponent on the unit determines the exponent on the scale factor.