Square Millimeters to Square Inches
Convert square millimeters (mm²) to square inches (in²). Type in either box; the other updates as you go.
How to convert square millimeters to square inches
To convert square millimeters to square inches, divide the number of square millimeters by 645.16.
Example
Convert 5 square millimeters to square inches:
Square Millimeter to square inch conversion chart
| Square Millimeters (mm²) | Square Inches (in²) |
|---|---|
| 1 mm² | 0.001550003 in² |
| 2 mm² | 0.003100006 in² |
| 3 mm² | 0.004650009 in² |
| 4 mm² | 0.006200012 in² |
| 5 mm² | 0.007750016 in² |
| 6 mm² | 0.009300019 in² |
| 7 mm² | 0.01085002 in² |
| 8 mm² | 0.01240002 in² |
| 9 mm² | 0.01395003 in² |
| 10 mm² | 0.01550003 in² |
| 12 mm² | 0.01860004 in² |
| 15 mm² | 0.02325005 in² |
| 20 mm² | 0.03100006 in² |
| 25 mm² | 0.03875008 in² |
| 30 mm² | 0.04650009 in² |
| 40 mm² | 0.06200012 in² |
| 50 mm² | 0.07750016 in² |
| 60 mm² | 0.09300019 in² |
| 70 mm² | 0.1085002 in² |
| 75 mm² | 0.1162502 in² |
| 80 mm² | 0.1240002 in² |
| 90 mm² | 0.1395003 in² |
| 100 mm² | 0.1550003 in² |
| 150 mm² | 0.2325005 in² |
| 200 mm² | 0.3100006 in² |
| 250 mm² | 0.3875008 in² |
| 500 mm² | 0.7750016 in² |
| 1,000 mm² | 1.550003 in² |
Going the other way? See the square inches to square millimeters chart.
About the units
Square Millimeter (mm²)
A square millimeter is one millionth of a square meter. Wire cross-sections are often given in square millimeters.
Square Inch (in²)
A square inch is the area of a square one inch on each side, exactly 6.4516 square centimeters.
Frequently asked questions
How many square inches are in a square millimeter?
There are 0.0015500031 square inches in a square millimeter.
How many square millimeters are in a square inch?
There are 645.16 square millimeters in a square inch.
How do you convert square millimeters to square inches?
To convert square millimeters to square inches, divide the number of square millimeters by 645.16.
What is 5 square millimeters in square inches?
5 square millimeters equals 0.00775002 square inches.
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