🪜 Stair Carpet Calculator
Enter your staircase dimensions to estimate the total carpet length and area needed to cover every tread and riser.
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What This Calculator Does
This calculator estimates how much stair carpet or a stair runner you need to cover a full flight of stairs, based on the number of steps and the size of each tread and riser.
The Formula
Each step consumes a length of carpet equal to the tread depth plus the riser height, since a wrapped runner covers both the flat step and the vertical face above it. Multiplying that per-step length by the number of steps gives the total running length, which is then multiplied by the stair width to get total area, and a waste allowance is added for pattern matching, pile direction, and cutting.
Good to Know
- Add extra length separately for any landing, curved winders, or extra carpet needed to wrap around a bullnose at the top or bottom step.
- Carpet is typically sold by the linear yard from a fixed roll width, so confirm your carpet’s roll width matches your stair width before ordering.
Last reviewed August 2026