The cost to carpet a room is three things added together — the carpet, the padding, and the labor to fit it. The one part that trips people up is the carpet quantity: you always buy more than the floor area, because carpet comes in fixed-width rolls. Here is how the whole estimate comes together.
What carpet installation costs
Installed carpet typically runs about $3.50–$11 per square foot ($30–$100 per square yard) all in — mid-grade residential carpet lands around $5–$8 per sq ft installed. A 12 × 15 ft room (180 sq ft) at $6/sq ft is about $1,080.
| Part | Typical price | Charged on |
|---|---|---|
| Carpet | $2–$8 / sq ft | carpet bought (incl. waste) |
| Padding / underlay | $0.30–$0.80 / sq ft | floor area |
| Installation labor | $0.50–$2 / sq ft | floor area |
How much carpet you need
Not just the floor area. Carpet comes on rolls of a fixed width — most commonly 12 ft, with 15 ft also stocked — and the roll rarely matches the room, so you buy the roll width and cut off the rest. A 10 × 14 ft room off a 12 ft roll buys 12 × 14 = 168 sq ft for 140 sq ft of floor — the extra 28 sq ft is the offcut down the side.
Carpet & Rug Installation Cost Calculator
Enter your room size, roll width and prices for the carpet, padding and labor cost — roll-width waste worked in.
Why you buy more than the room
Roll width. If the room is 10 ft wide and the roll is 12 ft, that 2 ft strip is waste you still pay for. A room wider than the roll needs two widths seamed together, which wastes more again. A good estimate lays the roll the way that wastes least (running its width along the longer wall to avoid a seam), then adds a trim allowance for doorways and pattern matching.
Square feet or square yards?
Both — US carpet has traditionally been priced per square yard, though per square foot is now common. 1 square yard = 9 square feet, so $54/yd² is $6/sq ft. If your quote is per yard, divide by 9 to compare it with a per-sq-ft price.
Don’t skip the padding
Padding (underlay) is what makes carpet feel good underfoot and last — most manufacturer warranties require it. It is priced separately on the floor area, roughly $0.30–$0.80 per sq ft, so it is its own line in the estimate. Reusing old padding on new carpet is usually a false economy.
Stairs and closets
Add closets and alcoves to the room size. Treat stairs separately — each standard step takes roughly 3–4 sq ft (0.3–0.4 m²) of carpet including the riser and a wrap allowance, and installers usually charge more per step for the fiddly labor. For a straight room the estimate is close; for a whole house with stairs, get an in-home measure.