How to Convert Square millimetres to Square centimetres (mm² to cm²)
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 millimetres into square centimetres by hand, with examples and a quick-reference table.
The conversion
To convert square millimetres to square centimetres, multiply the value by 0.01. To go the other way, divide by the same number (or multiply by 100). For a quick estimate, multiply by about 0.01.
Square centimetres = square millimetres × 0.01
Worked examples
- 3 mm² = 0.03 cm²
- 12.5 mm² = 0.125 cm²
- 75 mm² = 0.75 cm²
Square millimetres to Square centimetres table
| Square millimetres | Square centimetres |
|---|---|
| 1 mm² | 0.01 cm² |
| 2 mm² | 0.02 cm² |
| 5 mm² | 0.05 cm² |
| 10 mm² | 0.1 cm² |
| 20 mm² | 0.2 cm² |
| 25 mm² | 0.25 cm² |
| 50 mm² | 0.5 cm² |
| 100 mm² | 1 cm² |
| 250 mm² | 2.5 cm² |
| 500 mm² | 5 cm² |
| 1,000 mm² | 10 cm² |
Common questions
Is mm² to cm² 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 centimetres to Square millimetres converter.
Mistakes to avoid
Rounding the factor too early
Using 3 instead of 3.28 for feet per metre introduces an error of almost 9% before you have started.
Dropping the units
A bare number without a unit is easy to misread later. Always write the unit with the result.
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.
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.
A conversion table is handy for common values, but a calculator is faster and avoids interpolation errors for anything in between.
For everyday use, three or four significant figures are usually enough. Engineering, science and trade documents may need more, and rounding should happen only at the end of a calculation.
For any value, use the Square millimetres to Square centimetres Converter or browse all area converters.
Run your own numbers: Square millimetres to Square centimetres Converter