Square Footage Calculator

Calculates the area of a room, floor, yard or lot in square feet from its measurements, and also shows square yards, square meters and acres. Several shapes can be added together or subtracted, with an optional extra percentage and a cost estimate.

How to use

1. Choose the "Units", then pick a "Shape" for the first area and enter its measurements. Each length has a feet box and an inch box.
2. Press "Add another area" for each further part. Switch on "Subtract this area (cut-out)" for a part that is not included, such as a fireplace hearth.
3. If you are buying flooring or sod, set "Extra for waste".
4. Enter a "Price" and choose what the "Price is per" to see the "Estimated cost".

How it works

• Rectangle: length × width. Triangle: base × height ÷ 2. Circle: π × diameter² ÷ 4. Trapezoid: (side 1 + side 2) ÷ 2 × height. An L-shape is two rectangles added together.
• 1 square yard = 9 square feet, 1 square meter ≈ 10.764 square feet and 1 acre = 43,560 square feet.
• Your areas are saved in this browser.

Questions and answers

How do I calculate square footage of a room?

Multiply the length by the width in feet. A room 12 ft by 10 ft 6 in is 12 × 10.5 = 126 square feet.

How do I find the square footage of an L-shaped room?

Split it into two rectangles, find the area of each and add them. Choose "L-shape (two rectangles)" and enter both parts.

How do I convert square feet to square yards?

Divide by 9. For example, 126 square feet are 14 square yards. The result panel shows square yards automatically.

How much extra flooring should I buy?

The hint on the page suggests 5 to 15 percent for flooring or sod. Enter it under "Extra for waste" and the total includes it.