Square Footage Calculator

How to calculate square footage

Square footage is area measured in square feet — the number of one-foot squares that fit inside a shape. For anything rectangular that is a single multiplication:

The formula is a product rather than a sum because a square foot is itself a product: a square one foot on each side. Lay those squares out in rows and a rectangle 12 ft by 14 ft holds 12 of them in every row and 14 rows — 168 in total. That is also why the two sides can be swapped: 12 × 14 and 14 × 12 are the same number.

Step by step

1. Measure both sides in feet. Measure at floor level, along the longest straight run of each side.
2. Turn inches into a decimal. Divide the inches by 12 and add them on — 12 ft 6 in becomes 12.5 ft, 10 ft 3 in becomes 10.25 ft.
3. Multiply. Width × length gives the square footage.
4. Add up the parts. If the shape is not a plain rectangle, split it into rectangles, do each one separately and add the results.

Common sizes and their square footage

What people measure in square feet

• Flooring and carpet: laminate, tile and carpet are all priced per square foot, and buying about 10% extra covers cuts and pattern matching.
• Sheet material: a standard plywood sheet is 4 × 8 ft, so it covers 32 square feet — the quickest way to work out how many sheets a job takes.
• Paint and coatings: coverage is quoted in square feet per gallon or per litre.
• Land, lawns and turf: yards, garden beds and sod all get quoted by the square foot.
• Rent and property listings: in the United States and Canada, homes and offices are advertised by their square footage.

Where this formula stops working

• The shape must be rectangular. For an L-shaped room, split it into rectangles first. For a circle use π × radius², for a triangle half of base × height.
• Floor area is not wall area. A wall is height × length, and four walls of a 12 × 14 ft room come to far more than 168 square feet.
• A sloped surface covers more than its footprint. A pitched roof needs its own slope factor.
• Listed square footage may be measured differently. Property listings sometimes measure to the outside of the walls, so a floor you measure yourself will come out smaller.

Square feet in other units

One square foot is 0.092903 square meters, one ninth of a square yard, and one 43,560th of an acre. Every result page prints the metric and yard equivalents alongside the answer, and the site has dedicated converters for square feet to square meters and square feet to acres if that is the conversion you came for.