Square footage calculator
A room or area 12 ft long and 10 ft wide is 120 square feet, which is 13.33 square yards or 11.15 square meters.
The formulas
- Rectangle or square: length × width.
- Circle: π × (diameter ÷ 2)², about 0.785 × diameter².
- Triangle: base × height ÷ 2, with the height measured at right angles to the base.
- Trapezoid (two parallel sides): the average of the parallel sides × the distance between them.
Convert every measurement to feet before multiplying: divide inches by 12. For an L-shaped room or yard, split it into rectangles, work out each and add them. One square yard is 9 sq ft, one square meter is 10.764 sq ft, and an acre is 43,560 sq ft.
12 ft × 10 ft = 120 sq ft
Common room and yard sizes
| Size | Sq ft | Sq yd | Sq m |
|---|---|---|---|
| 8 × 10 ft | 80 | 8.9 | 7.4 |
| 10 × 10 ft | 100 | 11.1 | 9.3 |
| 10 × 12 ft | 120 | 13.3 | 11.1 |
| 12 × 12 ft | 144 | 16 | 13.4 |
| 12 × 15 ft | 180 | 20 | 16.7 |
| 12 × 20 ft | 240 | 26.7 | 22.3 |
| 15 × 20 ft | 300 | 33.3 | 27.9 |
| 20 × 20 ft | 400 | 44.4 | 37.2 |
| 20 × 24 ft | 480 | 53.3 | 44.6 |
| 24 × 30 ft | 720 | 80 | 66.9 |
What it takes to cover 300 sq ft
| Material | Amount | Also |
|---|---|---|
| Mulch, 3 in deep | 2.78 cu yd | 38 bags of 2 cu ft |
| Topsoil, 4 in deep | 3.70 cu yd | 67 bags of 1.5 cu ft |
| Gravel, 3 in deep | 2.78 cu yd | 3.75 tons |
| Concrete, 4 in slab | 3.70 cu yd | about $644 in ready-mix |
| Sod | 315 sq ft with 5% | 119 pieces of 16 × 24 in |
| 4 × 8 in pavers | 1485 pavers | with 10% for cuts |
Each material has its own calculator with depths, weights and prices: mulch, topsoil, gravel, concrete, sod and pavers.