Square Footage Calculator
Square footage is length times width. A 12 by 10 foot room is 120 square feet. Inches, extra rooms, and a waste allowance are included.
Length times width
How to calculate square feet: multiply length by width. Measure both sides in feet. If the tape shows inches, divide those inches by 12 first. 14 feet 6 inches is 14.5 feet.
| Room | Square feet |
|---|---|
| 10 ft × 10 ft | 100 |
| 12 ft × 10 ft | 120 |
| 12 ft × 15 ft | 180 |
| 15 ft × 20 ft | 300 |
An L-shaped room is two rectangles added together. A 12 by 10 foot piece plus an 8 by 6 foot piece is 168 square feet. Use Add another room for that.
Cubic feet
Cubic feet are length times width times height. A 12 by 10 by 8 foot space is 960 cubic feet. Switch to Cubic feet above. That total is volume, not floor area.
Questions
How do you calculate square feet?
Multiply length by width, with both measurements in feet. A room 12 feet by 10 feet is 120 square feet.
How do I convert inches when calculating square feet?
Divide the inches by 12 and add that to the feet. 14 feet 6 inches is 14.5 feet. Then multiply by the width.
How do I calculate an L-shaped room?
Split the room into rectangles, calculate each one, and add them. A 12 by 10 foot rectangle plus an 8 by 6 foot rectangle is 168 square feet.
How much extra material should I order?
A common waste allowance is 10 percent. For 120 square feet, order 132 square feet. Use more for a diagonal layout.