Stair Carpet Calculator — How Much Carpet for Stairs
Enter your staircase dimensions — number of steps, tread depth, riser height, and width — to find the total carpet area, waste allowance, and optional material cost.
m
m
m
%
Net area 5.418 m² + waste 0.271 m²
- 1
Carpet per step (tread + riser)
0.25 + 0.18 = 0.43 - 2
Net carpet area
14 × 0.43 × 0.9 = 5.418Steps × (tread + riser) × width — area before waste allowance. - 3
Total area with waste
5.418 × (1 + 5 ÷ 100) = 5.689
How does this calculator work?
Stair carpet area = steps × (tread depth + riser height) × stair width, then add a waste percentage for trimming. A typical 14-step staircase 0.9 m wide with 0.25 m treads and 0.18 m risers needs about 5.4 m² net, or roughly 5.7 m² with 5 % waste allowance.
Formula
How this is calculated
Stair carpet must cover both the horizontal tread (the surface you step on) and the vertical riser (the face of each step). The amount of carpet consumed along the stair direction for each step is therefore tread depth + riser height. Multiplying by the stair width gives the carpet area per step, and multiplying by the number of steps gives the net area — the minimum carpet needed if there were no cutting waste.
In practice, carpet must be cut to fit, so a waste allowance is added. Five percent is typical for plain carpet on a simple straight staircase; allow 10 % or more for patterned carpet (to match the repeat) or curved/winder stairs where cuts are angled. The waste percentage is applied to the net area to give the total area you should order.
Measure tread depth from the front nosing to the riser face (not including the nosing overhang on top). Riser height is the vertical distance between tread surfaces. Stair width is the clear width between handrails or walls. All inputs are in metres; typical domestic values are tread ≈ 0.22–0.28 m, riser ≈ 0.15–0.22 m, width ≈ 0.8–1.2 m. If your landing also needs carpet, calculate it separately as a rectangle and add to the stair total.
Frequently asked questions
For a fully carpeted staircase, yes — carpet wraps over the tread and down the riser. If you are fitting carpet tiles or separate stair treads only, leave the riser height at 0 and the calculator will give only the tread area.
Add 5 % for plain carpet on a straight staircase. Use 10 % or more if the carpet has a pattern repeat that must be matched step by step, or if the stairs include winders (angled steps) that require diagonal cuts.
A runner is simply a narrower stair width. Enter the runner width in the "Stair width" field (e.g. 0.6 m instead of the full 0.9 m stair width) and the calculation remains exactly the same.
Also known as
TG we-Calculate Editorial Team. (2026). Stair Carpet Calculator — How Much Carpet for Stairs [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/stair-carpet-calculator
TG we-Calculate Editorial Team. "Stair Carpet Calculator — How Much Carpet for Stairs." TG we-Calculate. 2026. https://we-calculate.com/calculator/stair-carpet-calculator.
TG we-Calculate Editorial Team, "Stair Carpet Calculator — How Much Carpet for Stairs," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/stair-carpet-calculator
@misc{wecalculate_stair_carpet_calculator, title = {Stair Carpet Calculator — How Much Carpet for Stairs}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/stair-carpet-calculator}}, year = {2026}, note = {TG we-Calculate} }
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