Square Footage Calculator
Enter a length and width to get the area in square feet and square yards, plus an optional material cost at your price per square foot.
What your result means
Square footage is length times width — the floor or surface area you're measuring. Square yards is that divided by nine, handy for carpet and concrete. Material cost multiplies the area by your price per square foot. For flooring and tile, add about 10% for waste and cuts. To estimate paint instead, use our paint calculator.
How to use this calculator
- Measure the length of the space in feet.
- Measure the width in feet.
- Multiply for square footage (the calculator does this).
- Add a price per square foot for a material cost, if you want one.
- For odd shapes, split into rectangles and add the areas together.
The formula
Area is simply length times width when both are in feet. Dividing by nine converts to square yards (nine square feet per square yard). Multiply the area by your unit price for a quick material cost.
Worked example
A room 12 ft by 12 ft is 144 square feet, or 16 square yards. At $5 a square foot for flooring, materials run about $720 — then add roughly 10%, or $72, for waste and trim cuts.
Quick square footage reference
| Dimensions | Square feet | Square yards |
|---|---|---|
| 10 × 10 ft | 100 | 11.1 |
| 12 × 12 ft | 144 | 16.0 |
| 12 × 16 ft | 192 | 21.3 |
| 20 × 20 ft | 400 | 44.4 |
| Odd shape | Split & add | — |
Tips & gotchas
- For L-shaped or odd rooms, break them into rectangles, find each area, and add them up.
- Carpet and concrete are often priced by the square yard — divide square feet by nine.
- Always order 5-10% extra flooring or tile for waste, cuts, and future repairs.
- Measure twice. A small error in one dimension scales across the whole area.
- For walls and ceilings, this same length-times-width works — just measure those surfaces.
Frequently asked questions
How do I calculate square footage?
Multiply length by width when both are in feet. A 12 by 12 ft room is 144 square feet. For odd shapes, split into rectangles and add the areas.
How many square feet in a square yard?
Nine. To convert square feet to square yards, divide by nine. 144 square feet is 16 square yards.
How much extra should I order for flooring?
Add 5 to 10% for waste, cuts, and pattern matching, and keep a little extra for future repairs.
How do I find the square footage of an odd-shaped room?
Divide it into rectangles, calculate each rectangle's area, then add them together for the total.
Does this work for walls and ceilings?
Yes. Square footage is length times width for any flat surface — floors, walls, ceilings, or countertops.
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Estimates only — see our full disclaimer.