Carpet Calculator — ft to sq yd, rolls, cost
How to use this calculator
Enter room dimensions (rectangle, L-shape, or custom area). Select carpet roll width (12 ft or 15 ft standard). The calculator determines the linear feet of carpet off the roll, number of seams, padding area, and tack strip perimeter. Waste is calculated based on seam matching.
Roll widths — 12 ft (standard) or 15 ft. Wider rolls reduce seams.
Padding — same area as carpet. Tack strips run the room perimeter minus doorways.
Saved Calculations
| Time | Shape | Area ft² | Sq Yd | Roll ft | Seams | Cost |
|---|
How to Calculate Carpet for a Room
Carpet comes off a continuous roll 12 ft or 15 ft wide, so the order quantity is driven by how many full-width strips run the room length — not just floor area. This tool lays out the strips, counts the seams those joins create, and converts the purchased rectangle to square yards (the unit US carpet is priced in). Pile direction is kept consistent across strips, which is why short strips are not nested into off-cuts; that conservative assumption matches how an installer actually orders cut-length carpet.
How to use
Pick a room shape, enter dimensions in feet/inches (or floor area plus perimeter for the Custom tab), and select the roll width your retailer stocks. Set waste to 5% for a single seamless strip, 10% for a typical multi-strip room, or 15% when a patterned carpet must be repeat-matched across seams. Open Cost to price carpet, padding and tack strip, and Installation for labor per square yard.
Formulas
strips = ceil(room width ÷ roll width). seams = strips − 1. linear feet = strips × room length × (1 + waste). carpet area = strips × roll width × room length × (1 + waste), then ÷ 9 → sq yd, rounded up. Padding = floor area ÷ 9 (sq yd). Tack strip = (perimeter − 3 ft door) ÷ 4 ft pieces. 1 sq yd = 9 sq ft.
Roll width & seams
Run carpet so the length axis follows the room's longest wall — a 13 ft 6 in wide room on a 12 ft roll needs two strips and one seam, but the same room on a 15 ft roll is seamless. Seams are the first place pile crushes and frays, so wider goods are worth the premium in hallways and high-traffic rooms. For a hard-surface alternative compare the flooring calculator (boxes & cost), and price wall finishes alongside the floor with the paint calculator or tile & grout calculator.
On install day
2025 US numbers to sanity-check a bid: carpet $2–6/sq ft ($18–54/sq yd) for residential nylon, padding $0.30–0.60/sq ft, tack strip $0.25–0.35/lf, installation $4–8/sq yd basic or $8–14/sq yd with furniture moved and old carpet hauled off. The #1 estimator miss is running carpet across the room's short axis to "save a strip" — you trade one seam for an off-pile that shows up in the first month of vacuuming; CRI 105 install guidance is to run the strips with the longest unbroken length parallel to the main light source. Order a few extra linear feet of tack strip for closets and bay windows, and double-check stair count separately — stairs are billed per step, not by sq yd.
FAQ
Why square yards, not square feet? US carpet has always been priced per square yard; 1 sq yd = 9 sq ft, so a 12×15 ft room is 20 sq yd of floor. Why is carpet ordered more than floor area? You buy full roll-width strips, so a 13 ft wide room still pulls a 15 ft strip — the extra width is unavoidable trim waste. Pattern match? Add 10–15% so the pattern repeat aligns across every seam. Working on the walls too? See the drywall calculator for board, tape and mud, or the brick wall calculator for masonry quantities.
