How Much Carpet Do I Need for Stairs? (2026 Guide)
How much carpet do I need for stairs? Each step needs its tread run plus riser: a straight run of about 13 steps at 36 in wide takes about 65 sq ft (7 sq yd).
How much carpet does one step need?
Carpet runs down a staircase as one strip, and each step needs the tread run (the flat surface you step on) plus the riser (the vertical face below it). A typical stair is 11 in + 7 in = 18 in — exactly 1.5 ft of carpet per step.
Measuring a straight run of stairs
With no landing or turn, the staircase is one continuous strip, so the math is short.
1. Count the steps
Count every step in the run you're covering.
2. Find the strip length
Multiply steps by the per-step amount: linear ft of carpet = steps × 1.5 ft (11 in tread + 7 in riser). Thirteen steps give 13 × 1.5 = 19.5 ft of strip.
3. Multiply by the stair width
Common widths are 27 in = 2.25 ft and 36 in = 3 ft. Area = strip length × width, so 13 steps at 36 in is 19.5 × 3 = 58.5 sq ft before waste. Not the standard 11 + 7 in? Use the stair carpet calculator.
Stair carpet by number of steps
Read off your staircase. Areas assume no waste and a straight, even run (sq yd = sq ft ÷ 9):
| Steps | Strip (linear ft) | 27 in wide (sq ft) | 27 in wide (sq yd) | 36 in wide (sq ft) | 36 in wide (sq yd) |
|---|---|---|---|---|---|
| 10 | 15 | 33.75 | 3.8 | 45 | 5 |
| 13 | 19.5 | 43.9 | 4.9 | 58.5 | 6.5 |
| 15 | 22.5 | 50.6 | 5.6 | 67.5 | 7.5 |
| 20 | 30 | 67.5 | 7.5 | 90 | 10 |
Buy with a 10% buffer (× 1.1): a 13-step, 36-in-wide staircase is about 65 sq ft ≈ 7.2 sq yd. Figures assume standard steps — go by your own measurements and your installer's takeoff.
Buying from a 12-ft-wide roll
Residential carpet comes on wide rolls — most commonly 12 ft wide. Any staircase under 144 in (27 in and 36 in both qualify) can be cut as a continuous strip along the roll, so no roll width is wasted.
Stairs with a turn, landing or winder
The straight-run rule applies per straight section, not the whole staircase:
- Measure flight by flight — each straight run is its own strip at steps × 1.5 ft; add the strips.
- Add landings as rectangles — a landing is length × width of carpeted floor, added to your total.
- Have winders measured on site — pie-shaped and curved steps don't follow straight-run math and rarely line up with a roll edge.
Seams and odd-shaped steps eat carpet, so buy 15–20% more for a staircase with a turn or winders.
Stair carpeting tips
- Pad goes in first — installers fit padding and tackless strips on each step before the carpet; keep pad coverage at least equal to the carpet.
- Buy about 10% extra — pattern matching, nosings, and cutting in at the ends of the run all use carpet.
- Turning stairs: plan 15–20% more — winders, landings and seams create offcuts a straight run never sees.
Planning the same project room by room? Start with carpet for a 12×12 room, or count the flooring boxes you'd need if you're comparing materials.
FAQ
How much carpet do I need for a 13-step staircase?
About 65 sq ft (7 sq yd) for a straight run at 36 in wide. Each step takes its tread run plus riser (11 + 7 = 18 in = 1.5 ft), so 13 steps form a 19.5 ft strip: 19.5 × 3 ≈ 58.5 sq ft, and a 10% buying buffer gives about 65 sq ft ≈ 7.2 sq yd. Confirm with your own measurements.
How do I measure carpet for stairs with a turn or landing?
Measure each straight flight with the tread-plus-riser rule and add the strips, then treat every landing as a rectangle (length × width). Winders and curved steps can't use the straight-run formula — have those measured on site — and buy 15–20% more for a turning staircase.
How wide is a roll of carpet?
Most residential carpet comes on 12-ft-wide rolls (some suppliers carry 13.5 ft or 15 ft). A 27 in or 36 in staircase is narrower than the roll, so the installer cuts a continuous strip down the roll and only the strip length counts toward what you buy.
Need a different size?
Our free calculators give you the exact answer in seconds.