Carpet Calculator — square yards for a room

How it works

Carpet is priced and sold by the square yard. Since one yard is 3 feet, one square yard is 3 × 3 = 9 square feet (NIST). So converting a floor area to square yards — with an allowance for waste — is:

square yards = area × (1 + waste) ÷ 9

Measure the floor area in square feet, add a waste allowance (around 10%) for seams, trimming and matching the pile direction, then divide by 9. Carpet comes on wide rolls (usually 12 feet), so real-world waste depends on how your room fits the roll width — awkward shapes waste more.

Unlike tile or flooring, the result is not rounded to whole units — carpet is cut from the roll to length, so a fractional square-yard figure is exactly what you order (the store rounds to the roll width for you).

Worked example

A 300 sq ft room with a 10% waste allowance is (300 × 1.1) ÷ 9 = 36.7 square yards. The definition itself — 9 square feet with no waste — is exactly 1 square yard. Doubling the room to 600 sq ft doubles the carpet to about 73.3 square yards.

Frequently asked questions

How do I calculate carpet in square yards?

Take the floor area in square feet, add a waste allowance, and divide by 9 (because 9 square feet make one square yard). For a 300 sq ft room with 10% waste, that is 36.7 square yards.

How many square feet are in a square yard?

Nine. A yard is 3 feet, so a square yard is 3 × 3 = 9 square feet. To convert square feet to square yards, divide by 9; to go the other way, multiply by 9.

How much waste should I allow for carpet?

About 10% is typical, covering seams, trimming and matching the pile direction. Rooms that fit the 12-foot roll width neatly waste less; long, narrow or L-shaped rooms, and stairs, waste more — allow 15% or measure the roll layout carefully.

Why does carpet come in specific widths?

Carpet is manufactured on wide rolls, most commonly 12 feet (also 13.5 and 15 ft). Your room is cut from that width, so the leftover strip is often waste. This is why the roll width, not just the area, affects how much you actually buy.

Should I round the square yards up?

Carpet is cut to length from the roll, so the fractional square-yard figure is what you order — the supplier works out the run length from the roll width. Keep the waste allowance in, and discuss seam placement with the installer for large or irregular rooms.

How is carpet different from flooring or tile?

The area math is the same, but carpet is sold by the square yard (÷9) rather than in boxes or individual pieces, and it is not counted in whole units. Tile and flooring come in discrete boxes or tiles, so those calculators round up to whole units.