Estimate how much concrete you need for straight concrete stairs, a stair flight with a landing, multiple identical flights or a compact stoop. Enter step count, tread depth, riser height, stair width and optional landing dimensions, then compare cubic feet, cubic yards and cubic metres. The Concrete Stair Calculator also supports a waste allowance, optional concrete bag estimate, material-only cost and downloadable PDF result.
All numeric entries start at 0. Select the stair type, enter valid dimensions, then press Calculate Stair Concrete. Results stay hidden until you calculate.
Your result will appear here after you press Calculate Stair Concrete.
The PDF includes stair type, step dimensions, landing or platform dimensions where applicable, base volume, waste allowance, rounded order volume, optional bag estimate and concrete-only cost.
A straight concrete stair is not a simple box. The estimator treats it as a solid stair body built from repeated tread-and-riser geometry, then converts the total cubic feet to cubic yards.
The calculator separates stair geometry from structural design and gives you the main material quantities needed for estimating.
Enter the number of risers in the stair flight.
Use actual tread depth and riser height from the stair design.
Compare the stair volume with ready-mix concrete quantities.
Add a practical allowance for real forms and placement conditions.
Apply your own local concrete rate per cubic yard.
Save the stair dimensions and concrete estimate for project planning.
Concrete stairs are more complicated to estimate than a simple slab because the shape changes at every step. A straight stair flight combines repeated tread-and-riser geometry across the full stair width. If a landing or top platform is part of the same concrete pour, that rectangular slab volume must be added to the stair flight.
The Concrete Stair Calculator uses the dimensions you enter rather than selecting code-compliant stair geometry for you. Number of risers, tread depth, riser height, stair width, landing size and reinforcement must come from the approved design or applicable project requirements.
One practical way to estimate a solid stair flight is to sum the volume of each step layer. With equal tread depths and equal riser heights, the stair cross-section is made from a sequence of rectangles. The calculator adds those rectangles and multiplies by stair width.
Volume = Stair Width × Tread Depth × Riser Height × [1 + 2 + 3 + ... + Number Of Risers]
The sum 1 + 2 + 3 + ... + n can be written as n(n+1)/2. The calculator uses this relationship internally after converting tread and riser dimensions from inches to feet.
Volume (ft³) = Width (ft) × Tread (ft) × Riser (ft) × n(n+1)/2
Each higher step sits on more concrete than the step below it. That means adding one more riser increases more than just one small rectangular block. The total stair cross-section grows as the triangular number n(n+1)/2, which is why long stair flights can require more concrete than expected.
Suppose a stair has 5 risers, each 7 inches high, with 11-inch treads and a stair width of 4 feet. The triangular number for 5 risers is 15. Convert 11 inches to 0.9167 ft and 7 inches to 0.5833 ft. Multiply 4 × 0.9167 × 0.5833 × 15 to get approximately 32.08 ft³, or about 1.188 yd³ before waste.
| Stair Example | Risers | Tread | Riser Height | Width | Approx. Volume |
|---|---|---|---|---|---|
| Small Steps | 3 | 11 in | 7 in | 3 ft | 0.357 yd³ |
| Entry Steps | 4 | 11 in | 7 in | 4 ft | 0.792 yd³ |
| Short Stair | 5 | 11 in | 7 in | 4 ft | 1.188 yd³ |
| Medium Stair | 6 | 11 in | 7 in | 4 ft | 1.663 yd³ |
| Wide Stair | 6 | 12 in | 7 in | 5 ft | 2.269 yd³ |
A landing is usually estimated as a rectangular slab: landing length × landing width × landing thickness. The Stair + Landing option calculates the stair flight first and adds the landing volume. Use the thickness specified by the project design rather than assuming the landing is the same thickness as another slab.
Landing Volume = Length (ft) × Width (ft) × [Thickness (in) ÷ 12]
If a project has several identical stair flights, use the Multiple Flights option. The calculator determines one stair flight and multiplies it by the number of identical flights. If the flights differ in riser count, tread depth, width or landing geometry, calculate each flight separately.
A concrete stoop often combines a short set of steps with a top platform. The Stoop / Steps option calculates the stair flight plus a rectangular top platform. This is useful for porches, exterior entry steps, service doors and similar compact concrete structures.
Total rise is the number of risers multiplied by riser height. For example, 6 risers at 7 inches each give a total rise of 42 inches, or 3.5 ft. Approximate stair run is related to tread depth and the number of treads, but actual layout must follow the project design because stair geometry and landing transitions can vary.
Stair width has a direct linear effect on concrete volume. A 5-foot-wide stair uses 25% more concrete than a 4-foot-wide stair with identical step geometry. Width must still come from the approved design and applicable access or egress requirements.
Small changes in riser height or tread depth can change the total volume across many steps. Because those dimensions repeat through the flight, always use the actual design measurements. Do not use the calculator to choose a comfortable or code-compliant rise and run.
There is no universal waste percentage for concrete stairs. Stair forms can be detailed and placement can involve multiple corners, risers and treads. Small losses can occur from overfilling, spills, pump or chute losses, form movement and finishing.
The calculator lets you enter your own contingency percentage. Keep the exact geometric volume visible, then select an allowance that fits the formwork accuracy, placement method and supplier order increments.
Bagged concrete can work for small steps or repairs when the total volume is limited. Enter the manufacturer-stated finished yield per bag in cubic feet. The calculator divides the volume after waste by the yield and rounds up to whole bags.
For a larger staircase, the bag count can become impractical. Use the concrete bags to cubic yards calculator if you want to convert an existing bag quantity into volume, or compare the stair result with ready-mix delivery.
Enter a concrete rate per cubic yard to estimate concrete material cost. The calculator multiplies the rounded order volume by your rate. This figure does not include stair forms, reinforcement, dowels, foundations, landing forms, labor, pump service, finishing, curing or demolition.
Concrete stairs can require substantial formwork because every tread and riser must be shaped and supported. Reinforcement placement, access, finishing and stripping forms can also affect labor. Exterior stairs may need foundations or frost protection, while architectural stairs can include special finishes or nosings.
This Concrete Stair Calculator estimates material volume only. It does not determine code-compliant rise and run, stair width, landings, reinforcement, foundations, handrails, guards, frost protection, structural capacity, concrete strength or accessibility requirements.
For related calculations, use the concrete floor calculator, concrete wall calculator, concrete volume calculator and concrete cost calculator.
The calculator estimates how much concrete the stair geometry contains. Safety and structural requirements remain separate.
Riser height and total rise must match the approved stair layout.
Tread depth affects both stair shape and concrete quantity.
Rebar and dowels must follow the project structural details.
Foundations and landings may require separate design and volume.
These examples demonstrate geometry only and are not stair-design recommendations.
| Stair Example | Step Geometry | Width | Base Volume | With 10% Allowance |
|---|---|---|---|---|
| 3-Riser Steps | 11 in Tread × 7 in Riser | 3 ft | 0.357 yd³ | 0.393 yd³ |
| 4-Riser Entry | 11 in Tread × 7 in Riser | 4 ft | 0.792 yd³ | 0.871 yd³ |
| 5-Riser Stair | 11 in Tread × 7 in Riser | 4 ft | 1.188 yd³ | 1.307 yd³ |
| 6-Riser Stair | 11 in Tread × 7 in Riser | 4 ft | 1.663 yd³ | 1.830 yd³ |
| Wide 6-Riser Stair | 12 in Tread × 7 in Riser | 5 ft | 2.269 yd³ | 2.495 yd³ |
Answers about steps, risers, treads, landings, stoops, bags, waste and concrete cost.
For a simple solid stair flight, calculate the triangular stair body plus the stepped tread-and-riser portion. The calculator uses step count, tread depth, riser height, stair width and optional landing dimensions.
Yes. Use the Straight Stair option and enter the number of risers, tread depth, riser height and stair width. Leave landing dimensions at 0 unless a landing is part of the pour.
Yes. The Stair + Landing option adds a rectangular landing slab to the stair volume using landing length, width and thickness.
Yes. Use the Multiple Flights option for identical stair flights and enter the number of flights.
Yes. Use the Stoop / Steps option for a compact solid stair block with a top platform.
No. Stair rise, run, width, landing geometry, reinforcement and code compliance must come from approved plans and applicable building requirements.
There is no universal percentage. Use an allowance that reflects formwork accuracy, spillage, pump or chute losses and supplier order increments.
Yes. Enter the manufacturer-stated finished yield per bag in cubic feet. The calculator divides the planned volume by that yield and rounds up to whole bags.
Yes. Enter a local concrete rate per cubic yard. The result is material-only and excludes forms, reinforcement, labor, pumping, finishing and delivery fees.
No. The calculator is intended for straight, block-style concrete stairs and landings. Curved, helical or architecturally complex stairs should be modeled from the actual design geometry.
A stair flight combines a sloped or triangular body with repeated tread-and-riser geometry, so it is more complex than multiplying one rectangular slab volume.
Yes. After calculating, use the PDF button to save stair dimensions, landing details, base volume, waste allowance, rounded order volume, optional bag estimate and cost.
Use approved project documents, applicable building requirements and authoritative concrete resources alongside any online material estimate.
Technical codes, standards and educational resources for structural concrete.
Visit ACIBuilding code resources covering stair, structural and construction requirements.
Visit ICC Digital CodesManufacturer estimating guidance for packaged concrete and common project shapes.
Visit QUIKRETE CalculatorWorkplace information about respirable crystalline silica hazards associated with concrete work.
Read OSHA Guidance