How to calculate carpet
Start with the room area, add a waste allowance, then convert to square yards if your supplier prices that way:
Carpet = length × width × (1 + waste %), then square yards = square feet ÷ 9
For L-shaped rooms, split the floor into rectangles, work out each, and add them together. Include closets you're carpeting.
How much waste to add
| Situation | Recommended waste |
|---|---|
| Simple room under 12 ft wide | 10% |
| Room wider than 12 ft (needs seams) | 10–15% |
| Patterned carpet | 15%+ |
| Stairs | 15–20% |
Roll width and seams
Most broadloom carpet comes on a 12-foot-wide roll (some lines also come in 13½ or 15 ft). That width is why carpet estimating isn't just area: a room wider than the roll needs a seam, and the offcut on either side becomes waste. A 14-ft-wide room, for example, is carpeted with a full 12-ft width plus a seamed-in strip — so you pay for more than the bare square footage. Plan seams to fall in low-traffic, low-light spots and to run the same direction as the main traffic and the window light.
Carpet types and durability
Carpet's feel and lifespan come down to the pile and the fiber:
- Cut pile (plush, Saxony). Soft and traditional; shows footprints and vacuum marks.
- Loop pile (Berber). Loops left uncut for durability — great for busy areas, though a snag can run.
- Frieze (twist). Tightly twisted cut pile that hides footprints and wear — a good casual, high-traffic choice.
- Nylon. The most durable and resilient fiber; best for stairs and heavy traffic.
- Polyester / PET. Soft and stain-resistant at a lower price, but it crushes sooner than nylon.
- Polypropylene (olefin). Cheap and moisture-resistant — common in Berbers and basements.
- Wool. Natural, luxurious, and naturally soil- and flame-resistant, at a premium price.
How much does carpet cost?
Carpet material runs about $2–$7 per square foot (roughly $18–$63 per square yard), with wool and high-face-weight nylon costing more. Budget separately for padding (about $0.30–$0.75 per sq ft) and professional installation (often $0.50–$1.50 per sq ft), plus tack strips and doorway transitions.
Don't forget
- Padding. You'll need carpet pad for the same area — it's sold separately, and a quality pad noticeably extends carpet life.
- Roll width matters. Standard rolls are 12 ft wide; wider rooms create seams and waste.
- Tack strips & transitions. Budget for tack strips around the perimeter and transition strips at doorways.
- Stairs use more. Each step needs extra to wrap the tread and riser — add 15–20% and measure carefully.