1 square millimeter to square inches
1 mm² = 0.00155 in². Change the amount below, or read the formula and the reference table further down.
1 square millimeter equals
square inches
1 mm² = 0.00155 in²
The formula
Square millimeters and square inches both measure area from the same zero, so a single multiplier does the job.
in² = mm² × 0.0015500031
Going the other way? Convert square inches to square millimeters.
Square millimeters to square inches table
Values either side of 1 mm².
| Square millimeters (mm²) | Square inches (in²) |
|---|---|
| -4 | -0.0062 |
| -3.5 | -0.005425 |
| -3 | -0.00465 |
| -2.5 | -0.003875 |
| -2 | -0.0031 |
| -1.5 | -0.002325 |
| -1 | -0.00155 |
| -0.5 | -0.000775 |
| 0 | 0 |
| 0.5 | 0.000775 |
| 1 | 0.00155 |
| 1.5 | 0.002325 |
| 2 | 0.0031 |
| 2.5 | 0.003875 |
| 3 | 0.00465 |
| 3.5 | 0.005425 |
| 4 | 0.0062 |
| 4.5 | 0.006975 |
| 5 | 0.00775 |
| 5.5 | 0.008525 |
| 6 | 0.0093 |
Questions people ask
- How many square inches are in a square millimeter?
- One square millimeter equals 0.0015500031 square inches.
- How do I convert square millimeters to square inches by hand?
- Multiply the number of square millimeters by 0.0015500031. For a rough check, 0.002 is close enough for most everyday use.
- What is 1 square millimeter in square inches?
- 1 square millimeter is 0.00155 square inches.
Calcuit generates this page from a unit table, so the factors here match every other page on the site.