The Stair Carpet Calculator makes stair covering simple and stress-free. Whether you have 13 steps, a spiral staircase, or L-shaped design, this tool provides accurate carpet estimates in metres or feet. Perfect for homeowners, DIY enthusiasts, or contractors who want to save costs, minimize waste, and achieve flawless results every time.
| Chosen roll width | – |
|---|---|
| Linear length required | – |
| Total carpet area | – |
| Waste estimate | – |
| Seam plan | – |
| Option | Width | Length | Area | Est. Waste | Material Cost | Pick |
|---|
| Piece | Qty | Width | Length | Notes |
|---|
Tip: For safety, many installers recommend stair carpet pile height ≤ ~½″ and firm underlay.
For full coverage (waterfall style), the per‑step piece length is riser + tread + nosing wrap plus trimming tolerance. Multiply by the number of steps to get the stair run. Add any landings as width × depth rectangles. If the carpet has a pattern repeat, round each piece dimension up to the nearest repeat in the matched direction(s). Apply a waste factor (10–15% typical) to cover cutting loss and on‑site adjustments.
For a runner, total linear length ≈ (riser + tread + nosing) × steps + landing depths. Runner width is set explicitly. Add binding (two long edges) and optional stair rods.
Whether you’re a homeowner or a contractor, the method is the same. The goal is to find how much carpet you need along the stair run (the length cut off the roll) and the width you need across each step. Use these steps or a stair carpet calculator to stay consistent.
| Step # | Tread (mm) | Riser (mm) | Nosing wrap (mm) | Tuck (mm) | Per‑step length (mm) |
|---|---|---|---|---|---|
| 1 | 270 | 180 | 40 | 20 | 510 |
| 2 | 270 | 180 | 40 | 20 | 510 |
| 3 | 270 | 180 | 40 | 20 | 510 |
| … | — | — | — | — | — |
Different stair shapes change how you use a carpet stair calculator. These simple images (inline SVG diagrams) highlight what to measure and where extra waste may occur.
There isn’t one “universal” answer—because tread depth, riser height, nosing shape, and installation style vary. But the maths is simple and mirrors any stair carpet calculator:
Per‑step length (mm) = Tread + Riser + Nosing Wrap + Tuck. Multiply by number of steps, add any landings, convert to metres, then adjust for waste.
If you’re carpeting full width on 900 mm‑wide stairs and using a 4.00 m roll, your area is roughly roll‑width × total length: 4.00 m × 6.63 m = 26.52 m². For a runner 700 mm wide, the area becomes 0.70 m × 6.63 m = 4.64 m². Add landings and a waste contingency (often 10%).
| Per‑step length (mm) | Steps | Total length (m) | Full‑width @ 0.90 m (m²) | Runner @ 0.70 m (m²) |
|---|---|---|---|---|
| 480 | 13 | 6.24 | 5.62 | 4.37 |
| 510 | 13 | 6.63 | 5.97 | 4.64 |
| 540 | 13 | 7.02 | 6.32 | 4.91 |
Use the calculator at the top to answer “how much carpet for 13 stairs in metres” for your exact measurements and allowance preferences.
| Carpet thickness | Nosing wrap (mm) | Tuck (mm) | Notes |
|---|---|---|---|
| Thin / low‑pile (≤7 mm) | 25–35 | 10–15 | Minimal bulk; tight cap is easier. |
| Medium (8–10 mm) | 30–45 | 15–20 | Most homes fall here. |
| Thick / plush (≥11 mm) | 40–60 | 20–25 | Plan extra to avoid stretching or visible shortfall. |
| Roll width | Also called | Useful for | Considerations |
|---|---|---|---|
| 3.66 m | 12 ft (North America) | Most rooms, straight stair flights | Check stair width vs runner; seam direction matters. |
| 4.00 m | Metric common width | Rooms and flights needing extra crosswise coverage | Convenient for 900 mm+ stairs. |
| 5.00 m | Wide goods | Large, open spaces; fewer seams | Heavier; transport & handling considerations. |
| Item | Value |
|---|---|
| Tread depth | 270 mm |
| Riser height | 180 mm |
| Nosing wrap | 40 mm |
| Tuck allowance | 20 mm |
| Per‑step length | 270 + 180 + 40 + 20 = 510 mm |
| Total length (13 steps) | 510 × 13 = 6,630 mm = 6.63 m |
| Full‑width area (0.90 m) | 0.90 × 6.63 = 5.97 m² |
| Runner area (0.70 m) | 0.70 × 6.63 = 4.64 m² |
| Waste (10%) | Add 0.66 m length (≈ 0.46–2.65 m² depending on width) |
It converts your step measurements (tread, riser, nosing wrap, tuck) into a per‑step length, multiplies by the number of steps, adds any landings, then converts the total into linear metres and square metres. It also considers whether you’re doing full‑width or a runner, and sometimes factors in waste automatically.
Yes. A carpet calculator stairs focuses on front‑to‑back length per step, while room calculators primarily compute length × width. Stairs also introduce extra allowances for the nosing wrap and tuck, which aren’t present in flat rooms.
Use the largest tread and riser you measure as your baseline, or split the flight into groups (e.g., top 6 vs bottom 7). Many installers measure each step and take the maximum for safety. For winders, template each triangular step or add generous extra length.
Using 270 mm tread, 180 mm riser, 40 mm nosing wrap, and 20 mm tuck, you get 510 mm per step. That’s roughly 6.63 m of linear length for 13 steps, plus landings and waste.
Per‑step length is essentially the same. Cap‑and‑band sometimes needs a few extra mm at the nosing for a crisp “cap.” Your carpet stair calculator can include a small add‑on for thick or tight wraps.
Common options are 3.66 m, 4.00 m, and 5.00 m. Ensure your required stair width (or runner width) fits across the roll with pile direction preserved. Wider rolls can reduce seams but may cost more and be heavier to handle.
Expect every step to be slightly different. Template each step or plan extra waste. The measurement method is the same—find the longest path over the nosing for each tread, then add allowances—just repeated per step.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.