How to Convert Square centimetres to Square millimetres (cm² to mm²)
Area conversions are everyday maths in Singapore property: HDB flats are listed in square metres while condo listings and PSF prices use square feet. This guide shows how to convert square centimetres into square millimetres by hand, with examples and a quick-reference table.
The conversion
To convert square centimetres to square millimetres, multiply the value by 100. To go the other way, divide by the same number (or multiply by 0.01). For a quick estimate, multiply by about 100.
Square millimetres = square centimetres × 100
Worked examples
- 3 cm² = 300 mm²
- 12.5 cm² = 1,250 mm²
- 75 cm² = 7,500 mm²
Square centimetres to Square millimetres table
| Square centimetres | Square millimetres |
|---|---|
| 1 cm² | 100 mm² |
| 2 cm² | 200 mm² |
| 5 cm² | 500 mm² |
| 10 cm² | 1,000 mm² |
| 20 cm² | 2,000 mm² |
| 25 cm² | 2,500 mm² |
| 50 cm² | 5,000 mm² |
| 100 cm² | 10,000 mm² |
| 250 cm² | 25,000 mm² |
| 500 cm² | 50,000 mm² |
| 1,000 cm² | 100,000 mm² |
Common questions
Is cm² to mm² exact?
The factors used here are the internationally defined values where they exist; results are rounded for display only.
How do I convert back?
Use the Square millimetres to Square centimetres converter.
Mistakes to avoid
Multiplying when you should divide
Converting to a smaller unit gives a bigger number, and converting to a larger unit gives a smaller one. If your answer moves the wrong way, you have inverted the factor.
Dropping the units
A bare number without a unit is easy to misread later. Always write the unit with the result.
Forgetting squared and cubed units
Area and volume factors are the length factor squared or cubed, so 1 m² is about 10.76 sq ft, not 3.28.
Background
Writing the units next to every number while you work is the simplest way to avoid mistakes. If the units do not cancel to leave the one you want, the calculation is set up wrongly.
Unit conversion is simply multiplication by a fixed ratio. The ratio between two units of the same quantity never changes, so once you know it you can convert any value in either direction.
Singapore adopted the metric system in the 1970s, replacing imperial units and traditional Chinese measures in most official uses. Metric units are now standard in schools, trade and government, but older units survive in property, markets and imported goods.
For any value, use the Square centimetres to Square millimetres Converter or browse all area converters.
Run your own numbers: Square centimetres to Square millimetres Converter