Square Inches Calculator

Multiply length by width in inches. A rectangle 8 in long and 10 in wide has an area of 8 × 10 = 80 square inches. For a circle use π × radius²: a radius of 5 in gives 78.5398 square inches. For a triangle use one half × base × height: a 12 in base with a 9 in height gives 54 square inches.

Exactly 144. One foot equals 12 inches, so one square foot equals 12 × 12 = 144 square inches. Divide square inches by 144 to get square feet: 288 square inches = 2 square feet.

Use square inches for small objects where square feet would give awkward tiny decimals: paper and photo sizes, phone and laptop screens, pizza and baking pans, craft projects, and labels. Use square feet for rooms, floors, and land. As a rule of thumb, if the area is under about 1 square foot (144 square inches), square inches read more naturally.

Multiply by 6.4516, the exact factor by definition (1 inch = 2.54 cm, so 1 in² = 2.54² = 6.4516 cm²). Example: 80 square inches = 80 × 6.4516 = 516.128 square centimeters.

Exactly 6,272,640. One acre is 43,560 square feet, and each square foot is 144 square inches, so 43,560 × 144 = 6,272,640 square inches per acre.

Use area = π × radius². Measure the radius (half the diameter) in inches, square it, and multiply by π ≈ 3.14159265. A circle with a 3 in radius has an area of π × 9 = 28.2743 square inches.

Take the square root of the area. A square of 144 square inches has a side of √144 = 12 inches. For a non-square area such as 50 square inches, the side of the equivalent square is √50 ≈ 7.0711 inches.

Yes. Inches squared is just the spoken form of square inches; both mean in², an area one inch by one inch. Do not confuse it with linear inches, which measure length only.