How to use this calculator
Select the shape that matches your space, rectangle, circle, triangle, or L-shape. Enter the dimensions in feet and the calculator instantly shows your total area in square feet, square yards, square meters, and acres.
Need to measure a complex space? Use the "Add another area" button to combine multiple shapes. The calculator adds them all together automatically. You can also enter a price per square foot to get an instant material cost estimate for flooring, paint, sod, or any other project.
Square footage formulas by shape
| Shape | Formula | Example |
|---|---|---|
| Rectangle / Square | Length × Width | 12 ft × 10 ft = 120 sq ft |
| Circle | π × Radius² | π × 5² = 78.54 sq ft |
| Triangle | ½ × Base × Height | ½ × 10 × 8 = 40 sq ft |
| L-Shape | (L1 × W1) + (L2 × W2) | (10 × 8) + (6 × 4) = 104 sq ft |
Common room sizes
| Room | Typical Size | Square Footage |
|---|---|---|
| Bedroom (small) | 10 × 10 ft | 100 sq ft |
| Bedroom (master) | 14 × 16 ft | 224 sq ft |
| Living Room | 12 × 18 ft | 216 sq ft |
| Kitchen | 10 × 12 ft | 120 sq ft |
| Bathroom | 5 × 8 ft | 40 sq ft |
| One-car Garage | 12 × 20 ft | 240 sq ft |
| Two-car Garage | 20 × 20 ft | 400 sq ft |
Frequently asked questions
How do I calculate square footage?
For a rectangle or square, multiply the length by the width in feet. For example, a 12 x 10 foot room is 120 square feet. For other shapes, use the appropriate formula: circles use π x radius², and triangles use ½ x base x height.
How do I convert square feet to square yards?
Divide the square footage by 9 to get square yards. There are 9 square feet in 1 square yard (3 feet x 3 feet = 9 square feet). For example, 270 square feet = 30 square yards.
How many square feet are in an acre?
There are 43,560 square feet in one acre. To convert square feet to acres, divide your total square footage by 43,560. For example, a 10,000 sq ft lot is about 0.23 acres.
How do I measure an L-shaped room?
Break the L-shape into two rectangles. Measure the length and width of each rectangle separately, calculate the area of each (length x width), and add them together for the total square footage.