Calculators
Square footage calculator
Runs in your browser · does not check building standards
Floor, wall and ceiling area of a room in square feet, with flooring waste and an optional second section for L-shaped rooms.
Result
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How it was calculated
How to use
- Measure: Measure length and width at floor level, wall to wall.
- Add sections: For an L-shaped room, enter the second rectangle as the extra section.
- Count openings: Count doors and windows for the wall area.
- Use the numbers: Take the floor area to flooring and rugs, and the wall area to paint or wallpaper.
How it is calculated
- Square feet = length (ft) × width (ft); inches ÷ 12 first
- L-shaped room = main rectangle + extra rectangle
- Wall area = perimeter × ceiling height − doors (20 sq ft) − windows (15 sq ft)
- An extra section is assumed to join along its longer side, adding its two short sides of wall
- Square meters = square feet ÷ 10.764; square yards = square feet ÷ 9
Examples
12 × 10 ft bedroom
12 × 10 = 120 sq ft of floor. With an 8 ft ceiling the walls are 44 ft × 8 ft = 352 sq ft, minus one door and two windows = 302 sq ft to paint.
L-shaped living room
Main area 16 × 12 ft (192 sq ft) plus a 6 × 8 ft dining nook (48 sq ft) = 240 sq ft of floor; order 264 sq ft of flooring at 10% waste.
Frequently asked questions
How do I calculate square feet of a room?
Multiply the length by the width, both in feet. A room 12 feet long and 10 feet wide is 120 square feet. Convert inches first by dividing by 12, so 10 ft 6 in is 10.5 ft.
How do I measure an L-shaped or irregular room?
Split it into rectangles, calculate each one, and add them together. Enter the second rectangle as the extra section.
How much extra flooring should I buy?
About 10% for a straight layout, about 15% for a diagonal layout or a room with many corners, and 15 to 20% for herringbone and other complex patterns. Check the manufacturer's guidance for the product.
How do I convert square feet to square meters?
Divide square feet by 10.764. 120 sq ft is about 11.15 m².
Keep planning with your measurements
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