161
Unit 17 Four-Sided Measure
Copyright by The Goodheart-Willcox Co., Inc.
Therefore, to change square inches to square millimeters, multiply the number of square
inches by 645.16.
1. 1 in2 = 1
×
645.16 = 645.16 mm2
2. 1,000 in2 = 1,000
×
645.16 = 645160 mm2
3. 2,304 in2 = 2,304
×
645.16 = 1486449 mm2 (rounded)
Square Millimeters to Square Inches
To convert square millimeters to square inches, divide the number of square millimeters by
645.16.
1. 645.16 mm2 = 645.16 ÷ 645.16 = 1 in2
2. 6000 mm2 = 6000 ÷ 645.16 = 9.3 in2 (rounded)
3. 500000 mm2 = 500000 ÷ 645.16 = 775 in2 (rounded)
From To Do
Square feet Square inches × 144
Square inches Square feet ÷ 144
Square inches Square millimeters × 645.16
Square millimeters Square inches ÷ 645.16