Concrete calculator
Concrete Steps Calculator
Calculate ready-mix and bag alternatives for solid, equal concrete steps and a separate landing.
Planning estimate, not a contractor quote. Review the assumptions and replace presets with local prices when available.
Method
How this calculator works
This tool models a flight whose bottom is level and whose individual step blocks stack upward. It is useful for checking a solid geometric volume; it does not represent hollow precast steps or an inclined structural stair slab. Confirm the actual construction geometry before relying on the quantity.
Flight ft³ = width ft × riser inches × tread inches × n × (n + 1) ÷ 288. Landing ft³ = width ft × separate landing length ft × landing depth inches ÷ 12. Apply one allowance to their sum.
Worked example
A realistic starting point
Three steps, 4 ft wide, with 7-inch risers and 11-inch treads contain 12.833 ft³ in the solid flight. With no separate landing and a 10% allowance, the result is 14.117 ft³: 24 bags yielding 0.6 ft³ each, or 0.75 yd³ when ready-mix is rounded to quarter yards.
What changes the answer
Factors worth checking
Equal risers and treads
The triangular-series formula assumes every step has the same rise and run. Unequal existing steps require a separate geometric takeoff.
Landing overlap
Only add a landing whose footprint is outside the calculated flight. Counting the same concrete as both a step and a landing overstates the volume.
Select the correct geometry
A sloped waist slab, hollow unit, or flight resting on fill contains a different amount of concrete. This tool intentionally does not approximate those designs.
Common questions
Concrete Steps FAQ
Is this the same as the stair calculator?
No. The stair calculator checks rise and run geometry. This tool calculates concrete volume for a particular solid shape.
Does it size reinforcing steel?
No. Reinforcement, supports, foundations, and compliant stair dimensions require the project specification.
Why use n × (n + 1) / 2?
A solid flight has blocks one riser high, two risers high, and so on. Adding these heights gives the triangular-number factor.
Evidence
Sources & review
- QUIKRETE — concrete mix data sheetNominal bag yields for this product. Other mixes can have different yields.
- NIST — SI units: volumeUnit relationships; supplier product coverage and prices remain separate inputs.
Published by Calcstead. Report a correction.
Method and source links reviewed September 6, 2026. Price presets are editable planning inputs and should be replaced with current local information.