How it works
area = length × width; square yards = area × (1 + waste%) ÷ 9; linear feet = ceil(area × (1 + waste%) ÷ roll width)
Carpet by room size (12-ft roll, 10% waste)
Carpet by room size (12-ft roll, 10% waste)
| Room size | Floor area | Square yards | Linear ft (12-ft roll) |
|---|---|---|---|
| 10 × 10 ft | 100 sq ft | 12.2 sq yd | 10 ft |
| 10 × 12 ft | 120 sq ft | 14.7 sq yd | 11 ft |
| 12 × 12 ft | 144 sq ft | 17.6 sq yd | 14 ft |
| 12 × 15 ft | 180 sq ft | 22.0 sq yd | 17 ft |
| 15 × 20 ft | 300 sq ft | 36.7 sq yd | 28 ft |
| 20 × 20 ft | 400 sq ft | 48.9 sq yd | 37 ft |
Square yards = room square footage × waste ÷ 9. Linear feet is how much you pull off a 12-ft-wide roll; you pay for the full roll width, so narrow rooms still waste the leftover strip. Includes 10% waste — add 15–20% for stairs, halls, and patterned carpet.
Frequently asked questions
How much carpet do I need for a room?
Multiply room length by width for square feet, add about 10% for waste, then divide by 9 to get square yards (how carpet is sold). A 12×12 room (144 sq ft) needs about 17.6 square yards; a 15×20 room about 36.7.
How do I convert square feet to square yards of carpet?
Divide square feet by 9, since one square yard is 3 ft × 3 ft = 9 square feet. So 144 sq ft ÷ 9 = 16 sq yd before waste, or about 17.6 sq yd once you add a 10% allowance for cuts and seams.
Why does carpet come in 12-foot widths?
Most broadloom carpet is made on 12-ft-wide looms (13.5 ft and 15 ft also exist). Because you buy the full roll width, a room narrower than 12 ft still uses a 12-ft-wide piece — the leftover strip is normal waste. Plan seams to run the length of the roll and toward the main light source.