Free tool
Square footage calculator
To find a room’s square footage, multiply its length by its width in feet: a 12 ft × 10 ft room is 120 sq ft. For an L-shaped room, split it into rectangles, work out each one and add them up. The calculator below does it for you, in square feet, square metres and square yards.
How the calculator works
Each section is a rectangle: its area is length × width. Cut-outs, such as a chimney breast or a corner that isn’t part of the room, are subtracted. The total is converted with the exact definitions: one foot is 0.3048 metres and one square foot is 0.09290304 square metres (NIST). One square yard is nine square feet.
Measuring an L-shaped room
- Sketch the room and draw a line that splits it into two rectangles.
- Measure the length and width of each rectangle along the walls.
- Add each rectangle as a section above. The total is the room’s floor area.
Our guide on how to measure the square footage of a room walks through it with a worked example.
Room area isn’t always a home’s “official” square footage
This calculator only multiplies the sizes you type. Official figures can follow other rules. For example, the U.S. Census Bureau counts finished floor area and, in concept, measures to the outside of the exterior walls (U.S. Census Bureau), and appraisers working to Fannie Mae’s guide must follow the ANSI square footage method (Fannie Mae Selling Guide B4-1.3-05). If a figure matters for a sale, a mortgage or a contract, ask the professional handling it.
Questions
How do I work out the square footage of a room?
Measure the length and the width in feet and multiply them. A room 12 ft long and 10 ft wide is 12 × 10 = 120 square feet.
How do I measure an L-shaped room?
Split the floor into rectangles that don’t overlap, work out each one, and add them together. In the calculator, add one section per rectangle. You can also take the whole outer rectangle and subtract the missing corner.
How many square feet are in a square metre?
About 10.764. One square foot is exactly 0.09290304 square metres (NIST), so one square metre is 1 ÷ 0.09290304 ≈ 10.764 square feet.
Can I enter feet and inches?
Yes. Choose “ft + in” and type the feet and the inches separately for each side.
Does it add extra for waste or cuts?
No. It gives the area of the dimensions you enter, nothing more. How much extra material to buy depends on the product, so check with the supplier.