Concrete Step Calculator
Sum the stepped solid volume and an optional landing, then convert the order volume to concrete bags using label yield.
- Stepped section volume
- 12.83 ft³ (0.48 yd³)
- Landing volume
- 0 ft³ (0 yd³)
- Order volume
- 14.12 ft³ (0.52 yd³)
- Rounding excess
- 0.28 ft³ (0.01 yd³)
Solid-step geometry only. This calculator does not select safe rise, run, reinforcement, or foundations.
Show calculation
width × rise × run × n(n+1)/2 + landing volume; then ÷ 0.6 ft³/bag and round upTransparent method and editable product assumptions. Verify current labels and project requirements.
How this calculator works
For a solid staircase with equal rise and run, successive treads contain one, two, three, and more rise-height layers. Their sum is n(n + 1)/2, multiplied by stair width, rise, and run.
An optional rectangular landing is calculated separately and added only when all three landing dimensions are entered. Waste is applied to the combined unrounded volume.
Bag count uses finished concrete yield from the product data sheet. Bag weight alone is not volume. The tool reports the rounding excess created by whole bags and does not select stair geometry or reinforcement.
Formula
Stepped volume = width × rise × run × n(n + 1) ÷ 2; total = stepped volume + landing volumeThe live substitution appears with your result.Control example: three solid steps
For 48 in width, 7 in rise, 11 in run, and three steps, the layer multiplier is 3 × 4 ÷ 2 = 6.
Net stepped volume is 48 × 7 × 11 × 6 ÷ 1,728 = 12.83 ft³ before landing and waste.
Assumptions and limits
- Steps are solid, equal, rectangular prisms.
- Landing does not overlap the stepped volume.
- Bag yield is finished mixed concrete volume.
- Rise, run, reinforcement, base, drainage, and safety requirements come from the project—not this calculator.
Common measuring mistakes
- Multiplying width × total rise × total run as one solid block.
- Counting a landing twice.
- Using dry bag size instead of published finished yield.
Sources
Product-specific values remain editable. These sources support the method and stated examples; they are not a universal substitute for your supplier’s current label.
- QUIKRETE Concrete Mix 1101 data sheet Lists approximate finished yields, including 0.60 ft³ for an 80 lb bag.
Questions people ask
Does this design safe stairs?
No. It only computes solid volume from dimensions you enter.
Can I add a landing?
Yes. Enter all three landing dimensions; leave them at zero when there is no separate landing.
Why does bag yield matter?
Different package sizes and mixes produce different finished volumes. Use the product’s published yield.