How it works
The formulas
triangle = ½ × base × height
circle = π × (diameter ÷ 2)²
total = area 1 + area 2 + area 3
Assumptions
- 1 sq yd = 9 sq ft (3 ft × 3 ft). 1 acre = 43,560 sq ft. 1 sq ft = 0.09290304 m².
- Metric: type meters. The sizes are converted to feet for the math, and the sq ft total always shows, with m² beside it.
- Measure the finished floor, wall to wall. Closets, alcoves and bay windows count as extra areas.
- This is the exact area. Materials need extra for cuts: flooring and tile hints include 10%, with 20 sq ft per flooring box (a typical carton; yours may differ).
Worked example: an L-shaped room
A 12 × 14 ft room with a 6 × 5 ft nook
- Main room: 12 × 14 = 168 sq ft
- Nook: 6 × 5 = 30 sq ft
- Add them: 168 + 30 = 198 sq ft
- In square yards: 198 ÷ 9 = 22 sq yd
Common room sizes in square feet
| Room | Sq ft | Sq yd | m² |
|---|---|---|---|
| 10 × 10 ft | 100 | 11.11 | 9.29 |
| 12 × 12 ft | 144 | 16 | 13.38 |
| 12 × 14 ft | 168 | 18.67 | 15.61 |
| 14 × 16 ft | 224 | 24.89 | 20.81 |
| 15 × 20 ft | 300 | 33.33 | 27.87 |
| 20 × 20 ft | 400 | 44.44 | 37.16 |
Length × width. For an L-shape, add the two rectangles: 168 + 30 = 198 sq ft.
Questions people ask
How do I calculate the square footage of a room?
Multiply the length by the width, both in feet. A 12 × 14 ft room is 12 × 14 = 168 sq ft. Measure wall to wall at the floor, and round each side to the nearest inch (an inch is 0.083 ft).
How do I calculate the square footage of an L-shaped room?
Split it into two rectangles, find the area of each and add them. A 12 × 14 ft room plus a 6 × 5 ft nook is 168 + 30 = 198 sq ft. In this calculator, put one rectangle in area 1 and the other in area 2.
How do I calculate the square footage of a circle?
Use π × (diameter ÷ 2)². A circle 10 ft across is 3.1416 × 5 × 5 = 78.5 sq ft. Pick Circle and type the diameter, the distance straight across the middle.
How do I convert square feet to square yards?
Divide by 9, because a square yard is 3 ft by 3 ft. 168 sq ft ÷ 9 = 18.67 sq yd. To go back, multiply square yards by 9. Carpet is often priced per square yard.
How many square feet are in an acre?
43,560 sq ft, or 4,840 sq yd. A 168 sq ft room is 0.0039 acres. A lot 100 ft by 100 ft is 10,000 sq ft, or 0.2296 acres.