How to work it out
- Measure the length and width of each room or section.
- Add an area for each one. L-shaped rooms work well as two rectangles.
- Add a waste allowance if you are buying flooring or tile. Ask your installer how much the layout needs.
- Enter a price per square foot to see the total cost.
The formulas
Rectangle: length × width. Circle: 3.14 × radius × radius. Triangle: base × height ÷ 2. To go from inches, divide by 144, because a square foot is 144 square inches.
A worked example
A room 12 ft 6 in by 10 ft is 12.5 × 10 = 125 sq ft. Add a closet of 4 × 3 ft, which is 12 sq ft, and the total is 137 sq ft.
Common questions
How do I calculate square feet from inches?
Multiply length by width in inches, then divide by 144. A piece 48 by 36 inches is 1,728 square inches, which is 12 sq ft.
How do I work out an L-shaped room?
Split it into two rectangles, add each as its own area, and the calculator adds them up.
How many square feet are in an acre?
43,560 sq ft.
How many square feet are in a square yard?
9 sq ft. To convert, divide square feet by 9.
Does home square footage include the walls and garage?
It depends on the purpose and who is measuring, and rules vary. For a sale, valuation or rental, check the standard your agent or appraiser uses.
Doing this job for a customer? Turn your numbers into a free written estimate on QuoteToPaid.