Convert square millimeters 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
Common values, rounded for reading.
| Square millimeters (mm²) | Square inches (in²) |
|---|---|
| 1 | 0.00155 |
| 2 | 0.0031 |
| 3 | 0.00465 |
| 4 | 0.0062 |
| 5 | 0.00775 |
| 6 | 0.0093 |
| 7 | 0.01085 |
| 8 | 0.0124 |
| 9 | 0.01395 |
| 10 | 0.0155 |
| 15 | 0.02325 |
| 20 | 0.031 |
| 25 | 0.03875 |
| 30 | 0.0465 |
| 40 | 0.062 |
| 50 | 0.0775 |
| 75 | 0.11625 |
| 100 | 0.155 |
| 250 | 0.387501 |
| 500 | 0.775002 |
| 1,000 | 1.55 |
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.