Convert square millimeter to square inch
1 mm² = 0.0015500031 in²
1 mm² = 0.00155 in²
1 mm² in every area unit
| square millimeter | 1 mm² |
| square centimeter | 0.01 cm² |
| square meter | 0.000001 m² |
| hectare | 1.00e-10 ha |
| square kilometer | 1.00e-12 km² |
| square inch | 0.00155 in² |
| square foot | 0.0000108 ft² |
| square yard | 0.0000012 yd² |
| acre | 2.47e-10 ac |
| square mile | 3.86e-13 mi² |
How the conversion works
Multiply by 0.0015500031 to go from square millimeter to square inch, or divide by it to go back. Every conversion on this site routes through the SI value (m²) rather than a table of pairwise factors, so a round-trip returns exactly what you started with.
Going the other way? square inch to square millimeter — 1 in² = 645.16 mm².
square millimeter to square inch — common values
| 1 mm² | 0.0015500031 in² |
| 2 mm² | 0.0031000062 in² |
| 3 mm² | 0.0046500093 in² |
| 5 mm² | 0.0077500155 in² |
| 10 mm² | 0.015500031 in² |
| 15 mm² | 0.023250047 in² |
| 20 mm² | 0.031000062 in² |
| 25 mm² | 0.038750078 in² |
| 50 mm² | 0.077500155 in² |
| 75 mm² | 0.11625023 in² |
| 100 mm² | 0.15500031 in² |
| 250 mm² | 0.38750078 in² |
| 500 mm² | 0.77500155 in² |
| 1000 mm² | 1.5500031 in² |
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