square feet to square inches calculator
This square feet to square inches calculator multiplies by 144 and also gives square yards, so 10 sq ft is 1,440 in² or 1.111 yd² using 12 × 12 inches.
Converting square feet to square inches
A square feet to square inches calculator multiplies an area in square feet by 144. Type the area and read the answer in square inches. The tool also shows the same area in square yards.
A square foot is a square that is 12 inches on each side. Lay a ruler along one edge and you count 12 inches. Fill the square with 1-inch tiles and you need 12 rows of 12 tiles. That is 144 tiles.
The formulas in plain words
- Square inches = square feet × 144.
- Square yards = square feet ÷ 9.
The 9 comes from a square yard being 3 ft by 3 ft, which holds 9 square feet. To go from square inches back to square feet, divide by 144.
Worked example: 10 square feet
- Square inches: 10 × 144 = 1,440 in²
- Square yards: 10 ÷ 9 = 1.111 yd²
Worked example: 2.5 square feet
A glass panel is 2.5 sq ft.
- Square inches: 2.5 × 144 = 360 in²
- Square yards: 2.5 ÷ 9 = 0.278 yd²
Conversion table
| Square feet | Square inches | Square yards |
|---|---|---|
| 1 | 144 | 0.111 |
| 5 | 720 | 0.556 |
| 25 | 3,600 | 2.778 |
| 100 | 14,400 | 11.111 |
Going the other direction
Sometimes you have square inches and need square feet. Divide by 144. A 600 in² piece is 600 ÷ 144 = 4.167 sq ft. A 3,600 in² panel is 25 sq ft.
If you have a rectangle in inches, multiply the two sides first. A board that is 24 in by 36 in has 864 in², and 864 ÷ 144 = 6 sq ft.
A quick way to picture it
Hold a sheet of paper that is 8.5 in by 11 in. It has 93.5 square inches, which is only about 0.65 of a square foot. It takes roughly one and a half sheets laid edge to edge to cover one square foot of floor. That gap between a sheet of paper and a floor tile is why the number 144 feels large the first time you see it.
Now imagine a tile that is 12 in by 12 in. It is one square foot, and 144 square inches. Cut it into 2 in by 2 in pieces and you get 36 pieces, each 4 square inches. Multiply 36 by 4 and you are back at 144.
Doing it without the tool
If you do not have the calculator, there is a shortcut. Multiply the square feet by 100, then add the square feet times 44. For 10 sq ft, 10 × 100 is 1,000 and 10 × 44 is 440, so you get 1,440. That is the same as multiplying by 144.
When you need each unit
Square inches show up in small-part work. Glass and mirrors, sheet metal, gaskets, and cabinet doors are often specified in them. Pressure ratings use pounds per square inch, so the area of a piston or plate in square inches turns a pressure into a force.
Square feet are the standard for rooms and building materials. Flooring, drywall, paint coverage, and roofing all use them. Square yards are used for carpet, sod, and some concrete flatwork.
Keeping all three straight avoids ordering the wrong amount of material. If a supplier lists carpet by the square yard, convert your room in square feet first. The square footage calculator helps you find the area.
Common mistakes
- Multiplying by 12. A linear foot has 12 inches, but area uses 144.
- Dividing by 12 on the way back. Use 144 in that direction too.
- Mixing units in a rectangle. If one side is in inches and the other is in feet, convert first.
- Rounding too early. For small parts, round only at the end.
- Confusing square inches with cubic inches. Volume needs a third dimension.
Related calculators
Use the square footage calculator to find the area of a room first. The tile calculator turns that area into a tile count, and the volume calculator adds depth when you need cubic units.
Frequently asked questions
How many square inches are in a square foot?
There are 144 square inches in 1 square foot. A square foot is 12 in by 12 in, and 12 × 12 = 144.
Why isn't it 12?
Twelve is the number of linear inches in a linear foot. Area multiplies two lengths, so the factor is squared. A square that is 12 in on each side has 12 rows of 12 square inches.
How do I convert square inches back to square feet?
Divide by 144. A piece of glass with 600 square inches has 600 ÷ 144 = 4.167 square feet.
How many square yards is a square foot?
One square foot is one ninth of a square yard, or 0.111 yd². The tool shows square yards next to square inches. 10 sq ft is 1.111 yd².
When would I use square inches?
Small parts and material specs often use square inches, such as glass, sheet metal, gaskets, and pressure over an area in psi. Larger surfaces such as floors and roofs use square feet.
Estimates only. Verify quantities with your supplier before purchasing.