About this calculator
Volume for a flight of solid poured steps, including the top landing or platform. Steps are treated as solid blocks down to the bottom slab level.
How it’s calculated
Each step is a block the full width of the flight. The bottom step is one riser high and each step up is one riser taller. The landing is the full height of the flight. Volume = width × riser × (tread × (n−1) × n ÷ 2 + landing × n).
Worked example
With these inputs:
- Number of risers (steps)
- 3
- Riser height
- 7 in
- Tread depth
- 11 in
- Step width
- 4 ft
- Top landing depth
- 3 ft
- Supply as
- Pre-mixed bags
- Bag size
- 80 lb
- Waste allowance
- 10%
the result is:
- Concrete needed
- 1.12 cu yd
- Total rise
- 1' 9"
- Total run (treads)
- 1' 10"
- Net volume
- 1.02 cu yd
- Ready-mix order (to ¼ yd)
- 1.25 cu yd
Tips from the trade
- Keep every riser the same height. A difference of more than ⅜" between steps is a trip hazard and fails inspection.
- If the steps sit on fill with a thinner concrete shell, this figure will overestimate. Work out the shell as slabs instead.
- See the stair calculator for riser and tread limits.
Results are estimates for planning and pricing. Check quantities against your drawings, the manufacturer’s data and local building codes before ordering.