Convert Square millimetres to Square centimetres
1 square millimetre is 0.01 cm². One square millimetre is exactly 0.01 square centimetres.
One square millimetre is 0.01 square centimetres. To convert square millimetres to square centimetres, multiply by 0.01; to go the other way, divide by 0.01 or multiply by 100. The factor is exact rather than rounded: it follows from NIST Office of Weights and Measures. A millionth of a square metre, because the millimetre is a thousandth of a metre and area squares the factor.
Factor checked against the defining standard · How we check
- Square millimetres × 0.01
1 * 0.010.01 cm²
1 square millimetre in every area unit
| Unit | Value | Exact factor |
|---|---|---|
| square inches | 0.0015500031 sq in | × 0.00155000310001 |
| square feet | 0.00001076391042 sq ft | × 0.0000107639104167 |
| square yards | 0.000001195990046 sq yd | × 0.0000011959900463 |
| acres | 0.0000000002471053815 ac | × 0.000000000247105381467 |
| square meters | 0.000001 m² | × 0.000001 |
| square millimetres (as entered) | 1 mm² | — |
| square centimetres | 0.01 cm² | × 0.01 |
| square kilometres | 0.000000000001 km² | × 0.000000000001 |
| square miles | 0 mi² | × 0.000000000000386102158542 |
| hectares | 0.0000000001 ha | × 0.0000000001 |
Factors are entered by hand from NIST Office of Weights and Measures rather than derived from a units library, so the ones that terminate are exact rather than rounded.
The same converter answers this pair however it is written: sqmm to sqcm is how the symbols are typed on a keyboard with no superscript on it.
How do you convert square millimetres to square centimetres? The converter and the working
- 1.Take the measurement in square millimetres.
- 2.Multiply by 0.01 — that is how many square centimetres fit in one square millimetre.
- 3.To go back the other way, divide by 0.01, or multiply by 100.
Worked example: 25 square millimetres to square centimetres
- Formula
- mm² × 0.01 = cm²
- Arithmetic
- 25 × 0.01 = 0.25 cm²
- Answer
- 25 mm² = 0.25 cm²
The factor is exact, so this figure is exact too — only the display is rounded.
Square millimetres to square centimetres conversion table
| Square millimetres | Square centimetres |
|---|---|
| 1 mm² | 0.01 cm² |
| 2 mm² | 0.02 cm² |
| 3 mm² | 0.03 cm² |
| 4 mm² | 0.04 cm² |
| 5 mm² | 0.05 cm² |
| 6 mm² | 0.06 cm² |
| 7 mm² | 0.07 cm² |
| 8 mm² | 0.08 cm² |
| 9 mm² | 0.09 cm² |
| 10 mm² | 0.1 cm² |
| 12 mm² | 0.12 cm² |
| 15 mm² | 0.15 cm² |
| 20 mm² | 0.2 cm² |
| 25 mm² | 0.25 cm² |
| 50 mm² | 0.5 cm² |
| 100 mm² | 1 cm² |
| 200 mm² | 2 cm² |
| 300 mm² | 3 cm² |
| 500 mm² | 5 cm² |
| 1000 mm² | 10 cm² |
| 2000 mm² | 20 cm² |
| 5000 mm² | 50 cm² |
| 10000 mm² | 100 cm² |
What is a square millimetre?
A millionth of a square metre, because the millimetre is a thousandth of a metre and area squares the factor. The working unit of engineering drawings and of cable cross-sections.
What is a square centimetre?
A ten-thousandth of a square metre — not a hundredth, which is the mistake squaring a prefix invites. 10,000 cm² to the square metre.
How many square centimetres are in a square millimetre?
One square millimetre is 0.01 square centimetres, exactly. Going the other way, one square centimetre is 100 square millimetres. Both figures come from the same defined relation rather than from a measurement, which is why they are the same today as they were in 1959.
Every area unit here
The whole group — 10 units with their symbols and the size of each one in square meters — is on the conversion index, along with every pair it makes. The table above already gives each of them relative to a square millimetre.
Cite this page
- APA
- Rule Calculator. (2026). Convert Square millimetres to square centimetres. Rule Calculator. https://rulecalculators.com/convert/square-millimeter-to-square-centimeter
- MLA
- "Convert Square millimetres to square centimetres." Rule Calculator, August 16, 2026, https://rulecalculators.com/convert/square-millimeter-to-square-centimeter.
- Chicago
- Rule Calculator. "Convert Square millimetres to square centimetres." Rule Calculator. Last reviewed August 16, 2026. https://rulecalculators.com/convert/square-millimeter-to-square-centimeter.
The date is when the figures on this page were last checked against their source, not the day you opened it. Add your own access date if your style needs one.
Questions people actually ask
- How many square centimetres are in a square millimetre?
- 0.01. A ten-thousandth of a square metre — not a hundredth, which is the mistake squaring a prefix invites. 10,000 cm² to the square metre.
- How do I convert square centimetres back to square millimetres?
- Divide by 0.01, or multiply by 100 — they are the same operation.
Other area conversions
Square centimetres to square millimetres — the same conversion the other way.