Centimetres to Millimetres
Centimetres to Millimetres (cm to mm) Converter
Convert from
- Centimetrescm
- Inchesin
- Metresm
- Kilometreskm
- Millimetresmm
- Micrometresµm
- Nanometresnm
- Feetft
- Yardsyd
- Milesmi
- Nautical milesnmi
- Milsmil
- US survey feetft (US survey)
- Astronomical unitsau
- Light-yearsly
- ÅngströmsÅ
1 centimetre = 10 millimetres
Default is 5 significant figures. “Units typed as” decides what words like gallon, pint or cup mean when you type them. Scientific input such as 1e15 or 2.5e-3 works in the value box; type unit names or a whole conversion in the unit picker’s search.
- 1 cm = 10 mm
- 5 cm = 50 mm
- 10 cm = 100 mm
- 25 cm = 250 mm
Shortcuts: / value box · S swap · Esc close the picker · Alt+C copy · Alt+L link · Alt+F favourite
How it’s calculated
Metric prefixes make this exact: 1 cm is 10 mm, so move the decimal point one place to the right.
1 cm = 10 mm (exact) · 1 mm = 0.1 cm (exact)
mm = cm × 10
- Multiply the value in centimetres by 10.
- To go back, divide by 10 (or multiply by 0.1).
- 1 cm = 10 mm · 1 mm = 0.1 cm
Step by step
Find the conversion factor
By definition 1 cm = 0.01 m and 1 mm = 0.001 m, so 1 cm = 10 mm. Source: BIPM SI Brochure (9th ed.).
Multiply by the factor written as a fraction
Put cm in the denominator so it cancels, leaving mm.
Calculate (unrounded)
Round the answer
Rounded to 5 significant figures.
Answer: 10 mm
Formula: mm = cm × 10. Factors last reviewed 2026-10-27.
Centimetres to millimetres conversion table
1 centimetre = 10 millimetres · 1 mm = 0.1 cm
- 1 centimetre = 10 millimetres
- 5 centimetres = 50 millimetres
- 10 centimetres = 100 millimetres
- 25 centimetres = 250 millimetres
- 100 centimetres = 1,000 millimetres
| Centimetres (cm) | Millimetres (mm) |
|---|---|
| 0.1 cm | 1 mm |
| 0.5 cm | 5 mm |
| 1 cm | 10 mm |
| 2 cm | 20 mm |
| 3 cm | 30 mm |
| 4 cm | 40 mm |
| 5 cm | 50 mm |
| 6 cm | 60 mm |
| 7 cm | 70 mm |
| 8 cm | 80 mm |
| 9 cm | 90 mm |
| 10 cm | 100 mm |
| 15 cm | 150 mm |
| 20 cm | 200 mm |
| 25 cm | 250 mm |
| 30 cm | 300 mm |
| 40 cm | 400 mm |
| 50 cm | 500 mm |
| 75 cm | 750 mm |
| 100 cm | 1,000 mm |
| 250 cm | 2,500 mm |
| 500 cm | 5,000 mm |
| 1,000 cm | 10,000 mm |
FAQ
How do I convert centimetres to millimetres?
Use mm = cm × 10. Multiply the value in centimetres by 10.
How many millimetres are in 1 centimetre?
1 centimetre (cm) equals 10 millimetres (mm).
How many centimetres are in 1 millimetre?
1 millimetre (mm) equals 0.1 centimetres (cm).
What is 10 cm in mm?
10 centimetres = 100 millimetres.
What is a centimetre?
Defined as exactly 1/100 of a metre.
What is a millimetre?
Defined as exactly 1/1,000 of a metre.
About these units
Centimetre (cm)
SI (metric)
1 cm = 0.01 m (exact)
Defined as exactly 1/100 of a metre.
Source: BIPM SI Brochure (9th ed.)
Millimetre (mm)
SI (metric)
1 mm = 0.001 m (exact)
Defined as exactly 1/1,000 of a metre.
Source: BIPM SI Brochure (9th ed.)