Concrete Steps Calculator

Enter the riser height, tread depth and width of concrete stairs, with a platform if there is one, and get the cubic yards and bags to buy, with each step's block worked out.

A ready-made setup of the Stair Calculator.

Estimates for planning, not professional advice. Read the full notice.

Steps

Inches, like 4 in

Inches, like 4 in

Feet and inches, like 12' 6"

Feet and inches, like 12' 6"

Fill in with the largest riser to take the riser count and height from the total rise.

Inches, like 4 in

Example: three concrete steps

51 80 lb bags

  • Concrete in the steps 27.42 ft³
  • To mix, with waste 30.16 ft³
  • To order as ready-mix 1.12 yd³

Estimate for planning, from what you entered and the product data shown. Check product labels and your supplier before you buy.

Shopping list

Example: three concrete steps
ItemSizeBuy
Concrete mix80 lb bag51

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    Worked example: three concrete steps

    Show the working
    1. Concrete in the first step 4 ft × 7 in × 3 ft = 7 ft³
    2. Concrete in the second step 4 ft × 7 in × 3 ft 11 in = 9.14 ft³
    3. Concrete in the third step 4 ft × 7 in × 4 ft 10 in = 11.28 ft³
    4. All the steps 7 ft³ + 9.138889 ft³ + 11.277778 ft³ = 27.42 ft³
    5. Add the waste allowance 27.416667 ft³ + 10%[1] = 30.16 ft³
    6. Divide by the bag's yield 30.158333 ft³ ÷ approx. 0.6 ft³[2] = 50.26 bags
    7. Round up once, to whole bags 50.26 bags = 51 × 80 lb bags

    Assumptions

    The figures behind the example. Sourced figures link to their source below; a default is a starting value to check against your label or supplier.

    Concrete waste allowance 10%[1]
    Default 10% is the top of NRMCA's 4% to 10% range.
    Yield of the 40 lb bag approx. 0.3 ft³[2]
    A 40 lb bag of QUIKRETE Concrete Mix 1101 yields about this many cubic feet, as the maker's own sheet states.
    Yield of the 50 lb bag approx. 0.375 ft³[2]
    A 50 lb bag of QUIKRETE Concrete Mix 1101 yields about this many cubic feet, as the maker's own sheet states.
    Yield of the 60 lb bag approx. 0.45 ft³[2]
    A 60 lb bag of QUIKRETE Concrete Mix 1101 yields about this many cubic feet, as the maker's own sheet states.
    Yield of the 80 lb bag approx. 0.6 ft³[2]
    An 80 lb bag of QUIKRETE Concrete Mix 1101 yields about this many cubic feet, as the maker's own sheet states.
    Yield of the 90 lb bag approx. 0.675 ft³[2]
    A 90 lb bag of QUIKRETE Concrete Mix 1101 yields about this many cubic feet, as the maker's own sheet states.

    Each step's block of concrete

    The depth of each step's block and its concrete, for the example steps, counted from the top step

    StepDepth of the blockConcrete
    Step 1 3 ft7 ft³
    Step 2 3 ft 11 in9.14 ft³
    Step 3 4 ft 10 in11.28 ft³

    A step's block runs from the front of its tread back to the wall or the platform, so lower steps hold more concrete. The bag yields come from QUIKRETE's published sheet. Product names are trademarks of their owners. HoneyDoMath is not affiliated with, sponsored by or endorsed by these makers.

    Your riser and tread beside the 2021 IRC values

    The example's riser height and tread depth beside the 2021 International Residential Code riser maximum and tread minimum

    DimensionYour example2021 IRC value
    Riser height (maximum) 7 in7.75 inModel-code (2021 IRC R311.7.5.1) maximum stair riser height; local adopted codes differ.
    Tread depth (minimum) 11 in10 inModel-code (2021 IRC R311.7.5.2) minimum stair tread depth; local adopted codes differ.

    Source: [3]

    The IRC values are a model code. Local codes and amendments differ; ask your building department which applies.

    Questions

    How much concrete for 3 steps?

    The example above works out three steps with a platform, step by step. Enter your own riser, tread, width and platform for your own volume and bags.

    How do I add a landing?

    Add it as a second item on the project list: a landing is a flat box of concrete, so enter its length, width and thickness. The two items share one bag count.

    What are the riser and tread limits for concrete stairs?

    The table on this page sets your riser and tread beside the 2021 IRC values, quoted in the sources. Local codes and amendments differ, so ask your building department.

    Can it work out the number of steps from the total rise?

    Yes. Fill in the total rise and the largest riser and the calculator divides the rise into whole risers, then uses each riser's equal height.

    Local codes and amendments differ; your building department decides.

    Sources (3)
    1. CIP 31, Ordering Ready Mixed Concrete, National Ready Mixed Concrete Association, 2000, 2016, 2023. Standards or industry body
      “Quantity of concrete ordered should be 4% to 10% more than an estimate calculated from the plan dimensions to account for contingencies.”
      Checked November 12, 2026. Figures and codes change; verify with the source. Back to where this is used
    2. QUIKRETE Concrete Mix No. 1101 data sheet, The Quikrete Companies, Revised October 2022. Manufacturer data
      “An 80 lb (36.2 kg) bag yields approximately 0.60 ft3 (17 L)”
      “A 40 lb (18.1 kg) bag yields approximately 0.30 ft3 (8.5 L)”
      “A 50 lb (22.6 kg) bag yields approximately 0.375 ft3 (10.6 L)”
      “A 60 lb (27.2 kg) bag yields approximately 0.45 ft3 (12.7 L)”
      “A 90 lb (40.8 kg) bag yields approximately 0.675 ft3 (19.1 L)”
      Per QUIKRETE's data sheet, checked Nov 12, 2026. Figures and codes change; verify with the source. Back to where this is used
    3. 2021 International Residential Code, Chapter 3 Building Planning, International Code Council, 2021 IRC. Code or government
      “The riser height shall be not more than 7 3/4 inches (196 mm).”
      “The tread depth shall be not less than 10 inches (254 mm).”
      Checked November 12, 2026. Figures and codes change; verify with the source. Back to where this is used

    These are summaries of what the sources say, not professional advice. Codes and product data change. Check with your building department and the product label about your own project.

    Sources

    • [1] National Ready Mixed Concrete Association, CIP 31, Ordering Ready Mixed Concrete. Checked November 12, 2026. https://www.nrmca.org/wp-content/uploads/2021/01/31pr.pdf
    • [2] QUIKRETE, QUIKRETE Concrete Mix No. 1101 data sheet. Checked November 12, 2026. https://www.quikrete.com/PDFs/DATA_SHEET-Concrete%20Mix%201101.pdf
    • [3] International Code Council, 2021 International Residential Code, Chapter 3 Building Planning. Checked November 12, 2026. https://codes.iccsafe.org/content/IRC2021P2/chapter-3-building-planning

    Made with HoneyDoMath.com. Estimates for planning; check product labels and local codes before you buy or build.