Square Footage Calculator
Calculate square footage from length and width for a rectangle, L-shape or circle — in feet, inches, yards or meters — with the area in sq ft, sq m and acres.
How to calculate square footage
Square footage is the area of a space — how much floor or ground it covers. For a rectangular room you multiply the length by the width, with both in feet. This calculator also handles L-shaped rooms (it adds two rectangles) and circles (area = π × radius²), and lets you measure in feet, inches, yards or meters — it converts to feet first, then shows the result in square feet, square meters and acres.
square feet = length (ft) × width (ft)
For example, a room 12 ft long and 10 ft wide is 12 × 10 = 120 square feet. Measuring in inches? Divide each side by 12 first, or work out the square inches and divide by 144 (since 12 × 12 = 144). Enter a price per square foot and the calculator also returns the total cost — handy for flooring, paint, turf or tiling.
Square footage of common rooms
| Room size | Square feet |
|---|---|
| 10 × 10 | 100 sq ft |
| 12 × 12 | 144 sq ft |
| 12 × 16 | 192 sq ft |
| 20 × 20 | 400 sq ft |
Square footage drives almost every home project — ordering flooring or carpet, buying paint, laying sod, or pricing a remodel. For an irregular space, split it into rectangles, find each area and add them, or use the L-shape mode above. Need volume instead of area? Try the cubic feet calculator.
Frequently asked questions
How do I calculate square footage?
Multiply length by width with both in feet: a room 12 ft by 10 ft is 12 × 10 = 120 square feet. Measuring in inches? Divide each measurement by 12 first, or work out the area in square inches and divide by 144. The calculator does the unit conversion for you.
How many square feet is a 12x12 room?
A 12 ft by 12 ft room is 12 × 12 = 144 square feet. The calculator gives the same answer instantly and also shows it in square meters (about 13.4 m²) and acres.
How many square feet is a 20x20 area?
A 20 ft by 20 ft area is 20 × 20 = 400 square feet (about 37.2 m²). For an L-shaped space, split it into two rectangles, work out each, and add them — or use the L-shape mode above.