square millimeter to square inch
Convert square millimeter (mm²) to square inch (in²). Use an editable area converter, conversion formula, and reference table.
1 mm² = 0.0015500031 in²
Conversion formula
One square millimeter equals 0.0015500031 square inch. Multiply your value in square millimeter by this factor to get square inch. For the reverse conversion, divide by the same factor.
Worked example
To convert 5 square millimeter:5 × 0.0015500031 = 0.0077500155 in²
Conversion table
| square millimeter (mm²) | square inch (in²) |
|---|---|
| 0.01 | 0.000015500031 |
| 0.1 | 0.00015500031 |
| 1 | 0.0015500031 |
| 2 | 0.0031000062 |
| 5 | 0.0077500155 |
| 10 | 0.015500031 |
| 25 | 0.0387500775 |
| 50 | 0.077500155 |
| 100 | 0.15500031 |
| 1000 | 1.5500031 |
About these measurements
Area measures a surface in two dimensions.
The base reference used here is the square meter. One square millimeter is 0.000001 base units; one square inch is 0.00064516 base units.
Important distinctions
Square a length factor to convert an area. Units with equal factors can have different conventional uses.
Precision
The converter uses stored conversion factors and floating-point arithmetic. Results display up to ten significant digits, switching to scientific notation for very small or large values. Keep the precision of your original measurement when reporting results.
Common questions
How do I convert mm² to in²?
Multiply the quantity in mm² by 0.0015500031. You can also type the value into the converter above.
Can I reverse the conversion?
Yes. Use the swap button or open the square inch to square millimeter converter.
Reference
NIST Guide to the SI — conversion factors and prefix conventions. SI prefixes scale units by powers of ten; the dimension-specific notes above describe the assumptions used on this page.
