13 straight stairs, 36 in wide, take 10.8 sq yd of carpet — 8.1 linear ft of a 12 ft roll, cut 3 steps across in 5 rows.
Each piece wraps the tread, the nose and the riser with the pile running down the stairs, as most manufacturers recommend. CRI 105 asks for a nose rounded 3/4–1 in so the carpet bends without cracking.
Carpet: Home Depot LifeProof typical (cached 2026). Pad: Caldwell full-roll memory-foam rebond. Tap any price to enter your store's.
This Old House (June 2026): labor $0.50–$1 per sq ft, stairs $11–$26 extra per step, removal $2–$3 per sq ft. “Free install” promos often exclude stairs, removal and furniture moving.
| Stair width | Pieces across | Rows | Linear ft | Sq yd |
|---|---|---|---|---|
| 30 in | 4 | 4 | 6.5 | 8.7 |
| 36 in | 3 | 5 | 8.1 | 10.8 |
| 42 in | 3 | 5 | 8.1 | 10.8 |
| 48 in | 2 | 7 | 11.4 | 15.2 |
13 steps fill 5 rows of 3 with 2 empty slots in the last row — enough to cover 2 more steps or a small landing at no extra carpet.
Up to 15 steps fit in these 5 rows; step 16 would start a new row and add 1.6 linear ft (2.2 sq yd).
A landing or winder steps need their own measurements; add the landing as a small room in the calculator above. CRI 105 asks for a nose rounded 3/4–1 in so the carpet bends without cracking.
The full method, material data and tips are on the main carpet calculator page.