Square Footage Calculator
Add one or more rooms or areas, choose a shape and enter the measurements. Get the total in square feet, square meters and square yards, plus a cost estimate with waste.
Cost estimate (optional)
Enter a price to estimate the cost.
How to use the Square Footage Calculator
- Choose your measuring unit: feet, feet + inches, inches, yards, meters or centimeters.
- Add your rooms or areas. For each one choose a shape and enter its measurements. Use the quantity box for identical rooms.
- Read the totals in square feet, square meters, square yards and acres. Every room also shows its own area.
- Optional: add a price per square foot or square meter and a waste percentage to estimate the cost of flooring, tile, paint or turf.
Square footage formulas
| Shape | Formula | Example |
|---|---|---|
| Rectangle | length × width | 12 ft × 10 ft = 120 sq ft |
| Square | side × side | 9 ft × 9 ft = 81 sq ft |
| L-shape | (length A × width A) + (length B × width B) | (12 × 10) + (8 × 6) = 168 sq ft |
| Circle | π × (diameter ÷ 2)² | π × 5² = 78.54 sq ft |
| Triangle | base × height ÷ 2 | 10 × 8 ÷ 2 = 40 sq ft |
| Trapezoid | (top + bottom) ÷ 2 × height | (8 + 12) ÷ 2 × 10 = 100 sq ft |
Area unit conversions
| From | To | Multiply by |
|---|---|---|
| Square feet | Square meters | 0.09290304 |
| Square meters | Square feet | 10.7639 |
| Square yards | Square feet | 9 |
| Acres | Square feet | 43,560 |
| Square inches | Square feet | 1 ÷ 144 |
Tips for measuring a room
- Measure wall to wall at floor level, and round up to the nearest inch or centimeter.
- Split irregular rooms into rectangles and add each part as its own area, or use the L-shape option.
- For flooring, include closets and areas under appliances that will be covered. For paint, measure wall area instead (width × height of each wall).
- Buy 5–10% extra flooring for cuts and waste, and keep a box for future repairs.
Frequently asked questions
How do I calculate square footage?
For a rectangle, multiply the length by the width in feet. A room 12 ft long and 10 ft wide is 12 × 10 = 120 square feet. For odd-shaped rooms, split them into rectangles and other simple shapes and add the areas together.
How do I calculate square footage of an L-shaped room?
Split the L into two rectangles, find the area of each and add them. In this calculator, pick the L-shape and enter the two rectangles' lengths and widths.
How do I convert square feet to square meters?
Multiply square feet by 0.09290304. For example, 200 sq ft × 0.0929 = 18.58 sq m. To go back, multiply square meters by 10.7639.
How much extra flooring should I buy?
Most installers add 5–10% for waste from cuts and mistakes. Use 10–15% for diagonal layouts, patterned tile or rooms with many corners.
How many square feet are in a square yard?
There are 9 square feet in one square yard, because a yard is 3 feet and 3 × 3 = 9. Carpet is often priced per square yard.
How do I measure a circle's area?
Measure the diameter (the distance across through the center) and use π × (diameter ÷ 2)². A circle 10 ft across has an area of about 78.54 sq ft.