Stair Carpet Calculator
Work out how much carpet a staircase needs. Enter the number of steps, the stair width, the tread, riser and nosing wrap, and a waste allowance, and get the carpet per step, the running length, the area in square feet and square yards (with waste) and an optional cost — plus by-steps and by-width tables and a downloadable PDF.
| Steps | Running length | Area (sq ft) | Sq yd |
|---|---|---|---|
| Enter a staircase to compare | |||
| Width | Area (sq ft) | Sq yd | Cost |
|---|---|---|---|
| Enter a staircase to compare | |||
How to use the stair carpet calculator
Four quick steps turn your step count and step size into carpet per step, running length and square yards to order — with by-steps and by-width tables, a chart and a downloadable report.
Count steps & width
Enter how many treads you’ll carpet and the carpet width across each step — full width or a runner.
Measure one step
Enter the tread depth, riser height and the nosing wrap around the front edge, in inches.
Add waste, landing & price
Pick a 0–15% waste allowance, add a landing depth if needed, and an optional price per square yard.
Read results & save a PDF
Get carpet per step, running length, sq ft and sq yd with waste and cost — then download a report.
How stair carpet is calculated
Carpet runs over each tread, wraps the nose and drops down the riser, so every step uses tread + riser + nosing. Multiply by the steps and the width for the area. Here is the exact math the calculator runs.
Worked example — 13 steps, 36″ wide, 10″ tread, 7.5″ riser, 1.5″ nosing, 10% waste
Per step: 10 + 7.5 + 1.5 = 19" · Running length: 13 × 19 = 247" ≈ 20.6 ft
Net area: 247 × 36 ÷ 144 ≈ 61.8 sq ft ≈ 6.86 sq yd
With waste: 61.8 × 1.10 ≈ 67.9 sq ft ≈ 7.55 sq yd · At $40/sq yd: 7.55 × $40 ≈ $302
≈ 7.55 square yards (67.9 sq ft) of carpet — about 20.6 ft of running length at 36″ wide.
Stair carpet reference charts
Handy lookups for carpet by number of steps, by stair or runner width, and how nosing, landings and pattern change the total.
| Steps | Running length | Area (sq ft) | Sq yd |
|---|---|---|---|
| 10 | 15.8 ft | 52.3 | 5.81 |
| 12 | 19.0 ft | 62.7 | 6.97 |
| 13 | 20.6 ft | 67.9 | 7.55 |
| 14 | 22.2 ft | 73.2 | 8.13 |
| 16 | 25.3 ft | 83.6 | 9.29 |
| 18 | 28.5 ft | 94.1 | 10.45 |
A typical floor-to-floor flight has 12–14 steps. Area and sq yd include 10% waste.
| Width | Area (sq ft) | Sq yd | Cost |
|---|---|---|---|
| 27″ runner | 50.9 | 5.66 | $226 |
| 30″ runner | 56.6 | 6.29 | $252 |
| 36″ full width | 67.9 | 7.55 | $302 |
| 42″ | 79.2 | 8.81 | $352 |
| 48″ | 90.6 | 10.06 | $403 |
Runners leave the sides of each step exposed. Cost is carpet only — pad, tackless strip and installation are extra.
| Option | Running length | Area with waste | Sq yd |
|---|---|---|---|
| Square nose (0″ wrap) | 19.0 ft | 62.6 sq ft | 6.95 |
| Standard (1.5″ wrap, 10%) | 20.6 ft | 67.9 sq ft | 7.55 |
| Patterned carpet (15% waste) | 20.6 ft | 71.0 sq ft | 7.89 |
| Add a 36″ landing | 23.6 ft | 77.8 sq ft | 8.65 |
Winders, flared or bullnose steps, seams and railing cut-outs can add more.
What the stair carpet calculator gives you
A step count and one step’s measurements give you the carpet to order.
Stair carpet at a glance
Who uses a stair carpet calculator
Whether you’re recarpeting the stairs or adding a runner, the same calculator tells you how much to buy.
Replacing worn stair carpet and wants a square-yard figure to compare quotes.
- Count every tread
- Measure one step
- Add the landing
Adding a runner over wood stairs and needs the running length and area at 27″ or 30″ wide.
- Enter runner width
- Read running length
- Use 15% for patterns
Pricing stair jobs and wants fast square yards and a material cost.
- Enter price per sq yd
- Compare widths
- Share the PDF
Tips for carpeting stairs
Stairs take more care than flat floors — these habits help the carpet fit and last.
Stair carpet calculator FAQ
Quick answers about how much carpet stairs need, measuring steps, runners, landings, waste and cost.
With a 10 inch tread, 7.5 inch riser and 1.5 inch nosing, each step uses 19 inches of carpet. Thirteen steps at 36 inches wide is 247 inches of running length, or about 61.8 sq ft (6.86 sq yd).
With 10% waste, order about 67.9 sq ft, or 7.55 square yards.
Add the tread depth, riser height and nosing wrap to get the carpet per step. Multiply by the number of steps, add any landing, then multiply by the width and divide by 144 for square feet.
Divide by 9 for square yards, then add your waste allowance.
Measure the tread from back to front, not counting the overhang, and the riser from the top of one tread to the next. Most treads are 10 to 11 inches and risers about 7 to 7.75 inches.
Add about 1 to 1.5 inches for the carpet to wrap the rounded nose, or 0 for a square edge.
Use the runner width instead of the full stair width. For 13 steps at 19 inches per step, a 27 inch runner needs about 50.9 sq ft (5.66 sq yd) with 10% waste.
A 30 inch runner needs about 56.6 sq ft (6.29 sq yd).
Yes, if the carpet continues onto a top or middle landing. Add the landing depth from front to back to the running length.
A 36 inch landing on 13 steps at 36 inches wide brings the total to about 77.8 sq ft (8.65 sq yd) with waste.
About 10% covers normal cuts and trimming. Use 15% for patterned carpet that has to line up step to step.
On 13 steps at 36 inches wide, 15% waste brings the order to about 7.89 square yards.
Multiply the square yards with waste by the price per square yard. Stair-grade carpet runs roughly $20 to $60 per sq yd for materials.
At $40 per sq yd, 13 full-width steps (7.55 sq yd) cost about $302 in carpet. Pad, tackless strip, staples and stair installation labor are extra.
This calculator measures the carpet the stairs actually use. Carpet comes on wide rolls, so the installer may need to buy a larger piece to cut the strips.
Winders, flared or bullnose steps, pattern repeat, seams and railing cut-outs can also add material. Confirm the final amount with your installer.
Estimate only — confirm with your installer. This calculator works in US units (inches, feet, square yards) and uses tread + riser + nosing wrap per step, times the stair width, plus a waste allowance. Winders, flared or bullnose steps, pattern repeat, roll width, seams and railing cut-outs can add material. Pad, tackless strip, staples and installation labor are not included. Measure your own stairs before ordering.