Square Footage Calculator
Measurement · Updated July 2026
Enter the length and width of your space to instantly get the total square footage — plus square yards and acres. Perfect for flooring, paint, landscaping, and real estate.
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Estimates only. Add extra for waste and confirm with your supplier.
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How do you calculate square footage?
Multiply the length by the width, both measured in feet. For example, a room 12 ft by 10 ft is 120 square feet (12 × 10 = 120).
Measuring irregular rooms
For anything that isn't a simple rectangle, split the space into rectangles, find each area, and add them together. For triangular sections, multiply base × height and divide by two. Round measurements to the nearest inch — small errors add up fast across a large floor.
Why square footage matters
Square footage is the starting point for flooring, paint, tile, and landscaping estimates, and it's the standard unit in real estate listings. Knowing it lets you compare quotes and buy the right amount of material without a second trip to the store.
How to use this calculator
- 1Measure the length of the area in feet.
- 2Measure the width of the area in feet.
- 3Multiply length × width to get square feet.
Frequently asked questions
How do I find square footage of an irregular room?
Break the space into rectangles, calculate the square footage of each, then add them together for the total.
How do I calculate square footage of a room?
Multiply the room's length by its width in feet. A 12 ft by 15 ft room is 180 square feet.
How many square feet are in a square yard?
One square yard equals 9 square feet (3 ft × 3 ft).
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