Square Footage Calculator
Split any space into rectangles, triangles and circles, then add or subtract them. That handles L-shaped rooms, bay windows, curved beds and cut-outs like kitchen islands. Enter feet and inches (10 ft 6 in) or just feet. A and B are length × width for a rectangle, base × height for a triangle (height measured square to the base, not along the slanted side), and A is the diameter for circles.
- Feet and inches or metric
- Combine and subtract shapes
- Converts to sq yd, m² and acres
2 Results
Updates as you type| Shape 1: Rectangle | 240 sq ft |
|---|---|
| Shape 2: Rectangle | 80 sq ft |
Quick answer
Square footage is length × width in feet. An L-shaped room split into a 20 × 12 ft and a 10 × 8 ft section is 240 + 80 = 320 sq ft (35.6 sq yd, 29.7 m²).
How to calculate square footage
- Rectangle: length × width
- Triangle: ½ × base × height
- Circle: π × (diameter ÷ 2)²
Measure in feet and inches; the calculator converts for you. By hand, divide the inches by 12 first: 10 ft 6 in is 10.5 ft, and 7 ft 3 in is 7.25 ft. A 10 ft 6 in × 7 ft 3 in room is 10.5 × 7.25 = 76.1 sq ft. Square feet ÷ 9 = square yards, and ÷ 10.764 = square metres.
Worked example: an L-shaped room
Split the L into two rectangles: 20 × 12 ft (240 sq ft) and 10 × 8 ft (80 sq ft). Total: 320 sq ft = 35.6 sq yd = 29.7 m².
Measuring tips
- Measure wall to wall at floor level, at the widest point.
- Round each measurement up to the nearest inch, but round cut-outs like kitchen islands down. A little extra beats a short order.
- Use this floor area in the flooring or tile calculator. For paint, measure the walls instead; the paint calculator does that for you.
Frequently asked questions
How do I calculate the square footage of an L-shaped room?
Divide it into two rectangles, calculate each (length × width) and add them. Our calculator lets you combine up to four shapes.
How do I calculate square footage with feet and inches?
Convert the inches to a decimal of a foot by dividing by 12, then multiply. For a room 12 ft 9 in by 10 ft 4 in: 12.75 × 10.333 = 131.75, about 131.8 sq ft. Don't multiply 12.9 by 10.4, because 9 inches is 0.75 ft, not 0.9 ft.
How many square feet are in a square yard?
Nine. A square yard is 3 ft × 3 ft.
How do I convert square feet to square metres?
Divide by 10.764. For example, 200 sq ft ≈ 18.6 m².
How many square feet are in an acre?
43,560 square feet. A square acre is about 208.7 ft on each side.
Last reviewed 2026-10-21. See how we calculate for our sources and assumptions.