By Zencalcy Editorial TeamLast reviewed About us
Stair carpet is measured as one continuous strip that climbs each riser and covers each tread. The run is the sum of every riser and tread, plus a little extra for the nosing that wraps the front edge of each step.
Carpet and padding needed to cover a flight of stairs.
run = risers × riser height + treads × (tread depth + nosing) area = run × width
Carpet is cut with the pile running across the stair, and a stair runner typically leaves 3 to 6 inches of the tread visible on each side. Patterned carpet needs extra length for pattern matching at each step.
| Symbol | Meaning |
|---|---|
| N | Number of risers. |
| h | Riser height. |
| d | Tread depth plus nosing. |
15 × 7.2 + 14 × 11.75 = 272.5 inches of carpet — about 22.7 linear feet, or 68 square feet at 36 inches wide.
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Yes. Unlike a floor, the carpet climbs each riser and turns onto each tread, so the run is the sum of both faces, not just the horizontal tread depth.
Results use standard construction estimating arithmetic: volumes from measured area and depth, unit weights from published material densities, and code-referenced spans or clearances where the page names a code. Quantities are rounded up to whole saleable units and include the stated waste allowance. These tools are planning aids, not structural design, and do not replace a licensed engineer, a local code check, or a contractor's site measurement.
Reference material used to build and check this calculator:
Last reviewed: September 2026. See how we build and check every tool on the about page.
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Content updated: September 2026