Square Footage Calculator
Work out the square footage of any area — rectangle, circle or a known area — in square feet, square metres, square yards and acres.
Square footage is the first number in almost every home improvement job — flooring, paint, turf, roofing. This calculator is that number, in every unit you might need.
Measure the length and width, and the area follows in square feet, metres, yards and acres.
Your results
Enter your measurements and press Calculate.
Quantities are rounded up to whole tiles, planks, boxes or bags, after the wastage allowance. Cost appears only when you enter a price.
Formula
All lengths are converted to a single unit before the calculation: 1 ft = 0.3048 m, 1 in = 25.4 mm, 1 ft² = 0.09290304 m², 1 yd² = 9 ft². Material quantities are rounded up — you cannot buy part of a tile, plank or bag.
How to use this calculator
- Choose the shape (rectangle, circle, or a known area).
- Enter the measurements.
- Read the area in square feet, metres, yards and acres.
- Use the Copy results button to copy the answer.
Worked example
| Room | 12 ft × 10 ft |
|---|---|
| Square footage | 12 × 10 = 120 ft² |
| Square metres | 120 × 0.09290304 = 11.15 m² |
| Square yards | 120 ÷ 9 = 13.33 yd² |
| Acres | 120 ÷ 43,560 = 0.0028 acres |
Check it by hand: every step above uses the formula in the box. If your numbers match the example inputs but the calculator gives a different answer, please report it via the contact page.
Frequently asked questions
How do I calculate square footage?
Multiply length by width for a rectangle (12 ft × 10 ft = 120 ft²), or use π × (diameter ÷ 2)² for a circle. This calculator does both, and converts the answer into metres, yards and acres.
How many square feet are in an acre?
43,560 ft². An acre is about 208.7 ft × 208.7 ft. This calculator shows acres for large areas.
How do I calculate square footage for an irregular room?
Split it into rectangles, calculate each one here, and add the totals. L-shaped rooms are two rectangles.
What is the difference between square feet and linear feet?
Square feet measure area (length × width); linear feet measure length only. Flooring, paint and turf are sold by the square foot; trim and fencing by the linear foot.
Related calculators
Estimates only. Results are for planning. Measure twice, confirm box coverage and tile sizes on the packaging you buy, and follow the manufacturer's instructions. See the disclaimer.