To find square footage, multiply the length by the width in feet. For an L-shaped or odd room, split it into rectangles, work out each one, and add them together, subtracting any cut-outs. This calculator does that in feet, inches, yards, metres or centimetres, and shows the total in square feet, square yards and square metres, with an optional allowance for waste.
| Formula | Area = length × width, summed over each rectangle |
|---|---|
| Units in | Feet, inches, yards, metres or centimetres |
| Units out | Square feet, square yards and square metres |
| Conversion | 1 sq ft = 0.09290304 m² (exact) |
By Ship AI Lab. Last updated .
How to work out square footage
Measure the length and width of the room in the same unit, multiply them, and the result is the area in that unit squared. If you measure in feet, the answer is in square feet. If your room is measured in inches, divide each side by 12 first, or pick inches in the calculator and it converts for you.
Square yards are square feet divided by 9, because a yard is 3 feet and a square yard is 3 by 3 feet. One square foot is exactly 0.09290304 square metres, so the calculator can give you metric figures for suppliers that quote in square metres.
L-shaped rooms, cut-outs and waste
Most rooms are not a single rectangle. Split an L-shape into two rectangles and add them, or measure the whole bounding rectangle and subtract the missing corner. Use the subtract button for things you will not cover, such as a kitchen island, a stair opening or a fitted cupboard.
Flooring, tile and paint are normally bought with a little extra to cover cuts and mistakes. The waste slider adds a percentage to your total. How much to add depends on the material and the layout, so follow the product maker’s advice for your case.
How to use the square footage calculator
- Pick a unitChoose feet, inches, yards, metres or centimetres to match how you measured.
- Enter each sectionType a length and width. Add a section for each extra rectangle in an L-shaped room.
- Subtract cut-outs, add wasteSubtract areas you will not cover, then slide the waste allowance if you are buying materials.
What this calculator cannot do
- It works with rectangles. Curved or angled walls need to be split into rectangles or measured another way.
- It does not know your material. Check the maker’s coverage and waste advice before you buy.
- The answer is only as good as your measurements. Measure twice, and measure at the widest points.
- It gives floor area. It does not work out wall area, volume or paint coats.
Square Footage Calculator questions, answered
How do I calculate square footage?
Multiply the length by the width in feet. For an L-shaped room, split it into rectangles, calculate each, and add them together. Subtract any cut-outs.
How do I convert square feet to square metres?
Multiply square feet by 0.09290304. The calculator shows both together, so you do not need to convert by hand.
How many square feet are in a square yard?
There are 9 square feet in a square yard, because a yard is 3 feet and 3 times 3 is 9.
How much extra should I add for waste?
It depends on the material, the layout and the cuts. Use the waste slider for an allowance and follow the product maker’s advice for your case.
Is anything I enter saved or sent?
No. The calculation runs in your browser, and nothing is stored or sent anywhere.