Carpet Area Calculator
Square feet
120.0
Square yards
13.33
How it works
Carpet is sold by the square yard and rolls come in standard widths (12 feet, 13.5 feet, 15 feet). The Carpet Area Calculator determines square footage, square yards, and the optimal roll width to minimize seams and waste.
**Roll width strategy** Selecting the right roll width dramatically affects waste. For a 14-foot-wide room: a 15-foot roll wastes only 1 foot of width, while two strips from a 12-foot roll create a visible seam. Seams in carpet are permanent and visible — minimizing seams is often worth accepting more waste.
**Seam placement rules** Never place seams in high-traffic paths, doorways, or under furniture legs. Seams in bedrooms can be hidden under the bed. Seams must run parallel to the primary light source in the room.
**Waste factors** Add 10% for standard rectangular rooms. Add 15% for rooms with diagonal walls, alcoves, or steps. Add 20% for patterned carpet requiring pattern matching. Stairs typically require 1 yard per step (tread plus riser plus tuck-under).
**Padding** Carpet is installed over a separate pad (underlay). Pad is sold separately and improves comfort, extends carpet life, and adds insulation. Calculate the same area as carpet; padding waste factor is lower (5%) since it does not require seam matching.
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Frequently Asked Questions
- Carpet is the visible fiber layer installed on top. Carpet pad (underlay) is the cushion layer installed beneath the carpet — typically 7/16 inch thick, made of rebond foam, memory foam, or rubber. Pad improves underfoot comfort, extends carpet life (cushions fiber impact), adds thermal and sound insulation, and helps carpet look better longer. Tack strip is a narrow wooden strip with angled tacks nailed around the room perimeter — the carpet is stretched over these tacks and secured at the edges, keeping it taut. For accurate installation: always install tack strips first, then pad (stapled or glued to subfloor), then stretch and tack the carpet.
- Measure the maximum width and length of the room — always measure the widest and longest points, including alcoves, closets, and bay windows that extend beyond the main rectangle. Sketch the room on paper, noting all protrusions. Add 3–4 inches to each dimension for installation waste (tucking, trimming). For L-shaped or non-rectangular rooms, sketch the shape and calculate as rectangles plus or minus the non-rectangular areas. For stairs, count each tread and riser as a separate measurement (standard: measure tread depth + riser height + 3 inches for tucking per step, multiply by number of steps, multiply by stair width).
- Professional installation of a 12×15-foot bedroom: 1–2 hours. A full house (3 bedrooms, living room, stairs): typically one full day. DIY carpet installation requires renting a power stretcher (knee kickers work but leave carpet less tightly stretched and prone to wrinkling over time) and a carpet knife. Cutting seams straight and invisible, stretching properly, and making tight transitions to hard floors are the most skill-intensive steps. Most beginners can handle a rectangular room without seams. Seaming and irregular rooms are significantly harder. Stairs are the most difficult and typically benefit most from professional installation.
- Carpet is sold by the square yard in the US. Conversion: square yards = square feet ÷ 9. A 12×15-foot room = 180 square feet = 180 ÷ 9 = 20 square yards. Since carpet comes in rolls of fixed width, you may need more square yards than the pure area calculation to minimize seams. Example: for a 14-foot-wide room requiring a 15-foot roll, you buy 15 feet of width even though you only use 14 feet — the extra foot is unavoidable waste. Your installer will calculate exact linear feet of roll needed based on your room dimensions and roll width, which determines actual cost.