How to calculate square footage
For a rectangular room, measure the length and the width in feet and multiply them. A room 12 feet long and 14 feet wide is 168 square feet. Measure wall to wall at floor level, and round to the nearest inch or centimeter.
For other shapes, use the matching formula, which the calculator applies for you:
- Rectangle or square: length times width.
- Triangle: base times height, divided by two.
- Circle: 3.1416 times the radius squared, or 0.785 times the diameter squared.
Measuring L shaped and irregular rooms
Split any irregular room into simple shapes. An L shaped room becomes two rectangles: measure each one separately, calculate its area and add them together. A room with a bay window is a rectangle plus a small rectangle or trapezoid. A room with an angled wall is a rectangle plus a triangle. Add each piece as its own section above and the calculator totals them.
Square feet, meters and yards
| To convert | Multiply by |
|---|---|
| Square feet to square meters | 0.0929 |
| Square meters to square feet | 10.764 |
| Square feet to square yards | 0.1111 (divide by 9) |
| Square yards to square feet | 9 |
Carpet is often priced per square yard in the US, while tile, laminate and paint coverage use square feet, and most of the world uses square meters. The calculator shows all three so you can compare quotes easily.
What to do with the number
Total floor area is the base for most home projects. Add a waste allowance before ordering flooring or tile, which our flooring calculator and tile calculator do automatically. For inspiration, see our budget home improvement ideas and small space home office ideas.
