SquareFootage
Actualizado July 2026

Stairs Square Footage Calculator

Count the tread and the riser on every step, multiply by the stair width, and see exactly how much carpet or flooring your staircase needs.

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Unidades
m
cm
m
cm
12 m15 m

Área total

1,938ft²

Metros cuadrados

180

Yardas cuadradas

215.3 yd²

Qué significa

To calculate the square footage of stairs, add each step's tread depth and riser height, because carpet wraps over both surfaces. A typical step is about 10.5 in of tread plus 7.5 in of riser — roughly 18 in (1.5 ft) of run. Multiply that by the stair width (about 3 ft) for ≈4.5 sq ft per step. A 13-step staircase covers about 58.5 sq ft.

Fórmula y guía

Cómo se calcula

Stairs are area, but not flat area — flooring and carpet cover both the horizontal tread you step on and the vertical riser at the front of each step. That is why each step counts for more run than its tread depth alone.

  1. 1Measure one step's tread depth and riser height in inches, then add them (e.g. 10.5 + 7.5 = 18 in) and divide by 12 to get the covered run per step in feet (1.5 ft).
  2. 2Measure the stair width in inches and divide by 12 to get feet (a standard 36 in stair is 3 ft).
  3. 3Multiply run per step × width for the area of one step (1.5 ft × 3 ft = 4.5 sq ft), then multiply by the number of steps.
  4. 4Add any landings as separate rectangles (length × width) and include a waste allowance before ordering.
Ejemplo resuelto

Míralo en números

Covered run per step (10.5 in tread + 7.5 in riser)1.5 ft
Stair width (36 in)3 ft
Area per step (1.5 ft × 3 ft)4.5 sq ft
13 steps × 4.5 sq ft≈ 58.5 sq ft

13 steps × 1.5 ft (tread + riser) × 3 ft width ≈ 58.5 sq ft, before landings and waste.

Precisión y supuestos

  • Each step counts the tread plus the riser, because carpet and stair runners wrap over both surfaces.
  • Landings are measured separately as flat rectangles (length × width) and added to the step total.
  • Add about 10% waste for carpet — stairs need extra for pattern matching, wrapping, and trimming.
  • Stair width includes any tread overhang (nosing), so measure the full covered width at the front edge.

Consejos y reglas clave

  • A typical residential step is about 10–11 in of tread and 7–7.75 in of riser, giving ≈1.5 ft of covered run.
  • Standard stair width is about 36 in (3 ft), so most straight steps cover roughly 4.5 sq ft each.
  • A common 13-step flight runs about 58–60 sq ft before you add landings.
  • The embedded calculator computes width × total run — enter 3 ft × (steps × 1.5 ft) to approximate a full flight.
Casos de uso

Para quién es esta calculadora

Carpet on stairs

Carpet wraps the tread and the riser, so count both surfaces per step and add ~10% for trimming.

Stair runners

A runner covers a center strip — use your runner width instead of the full stair width, times the same per-step run.

Flooring and treads

For hardwood or laminate treads and risers, the tread-plus-riser run tells you how much stock each step needs.

How to calculate the square footage of stairs

Measuring stairs trips people up because a staircase is not a flat floor — every step has a horizontal tread and a vertical riser, and most coverings wrap over both. If you only count the tread you step on, you will come up short by roughly 40% and order far too little material. The reliable method is to work one step at a time: add the tread depth and the riser height to get the covered run for a single step, then multiply by the stair width and the number of steps.

In practice a typical step has a tread around 10.5 inches and a riser around 7.5 inches, which adds up to 18 inches — about 1.5 feet of covered run. On a standard 36-inch (3-foot) wide staircase, that is 4.5 square feet per step. A common flight of 13 steps therefore covers about 58.5 square feet. Measure your own tread, riser, and width, though, because older homes and custom builds vary. The calculator above works as a rectangle, so enter your stair width and a length of steps × 1.5 ft to approximate the whole flight in one shot.

Why the riser counts (and landings do not)

The riser is the small vertical face between one tread and the next. When you install carpet or a runner, the material folds down over the front edge of each tread and covers that riser before reaching the next step. That vertical span is real surface area, so it has to be in your total. Hardwood and laminate installs treat the riser the same way, either with a matching riser board or a wrapped nosing.

Landings are the exception. A landing is a flat platform, so you measure it like any other floor — length times width — and add it to your step total as a separate rectangle. Keeping steps and landings on separate lines stops you from accidentally applying the tread-plus-riser rule to a flat surface that does not have risers.

Turning square footage into a material order

Once you have the total, add a waste allowance before you buy. Stairs demand more waste than a plain floor because each piece is small, patterns must line up from step to step, and carpet has to be cut and wrapped at every nosing — around 10% is a safe starting point. If you are covering the stairs and adjoining rooms in the same flooring run, total everything first so you can buy from consistent dye lots.

From there, multiply the square footage by your price per square foot to budget the job. Carpet, runners, and hardwood treads are all sold by area, so an accurate stair figure is what keeps a quote honest and prevents a second trip to the supplier.

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Preguntas

Preguntas sobre la calculadora de Stairs

Add each step's tread depth and riser height, since coverings wrap over both. A typical step is 10.5 in tread + 7.5 in riser = 18 in, or 1.5 ft of run. Multiply by the stair width (about 3 ft) for 4.5 sq ft per step, then by the number of steps. Thirteen steps come to about 58.5 sq ft.

Yes. The riser is the vertical face at the front of each step, and carpet, runners, and wrapped flooring all cover it. Skipping the riser undercounts each step by roughly 7–8 inches of run and leaves you short on material. Always add the riser height to the tread depth before multiplying by width.

For a standard 13-step flight about 36 in wide, plan on roughly 58–60 sq ft, then add about 10% waste for trimming and pattern matching — call it 65 sq ft. Adjust for your own tread, riser, and width, and add any landings as separate rectangles before ordering.

A landing is a flat platform with no risers, so measure it like a floor: length times width in feet, then multiply for its area. Add that figure to your step total as a separate rectangle. Keep landings and steps on separate lines so you only apply the tread-plus-riser rule to the actual steps.

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