Solid poured steps are a stack of blocks: the bottom step runs the full depth of the stairs and each step above is one tread shorter. Enter the number of steps, the rise, the tread depth and the width to get the concrete in cubic yards and bags.
Concrete steps formula
Volume = width × tread depth × rise × n × (n + 1) ÷ 2 (all in feet) Landing = width × landing depth × total height Cubic yards = cubic feet ÷ 27
Worked example: 4 steps, 7 in rise, 11 in tread, 4 ft wide
- Sum of step heights: 1 + 2 + 3 + 4 = 10 risers.
- Volume: 4 × (11 ÷ 12) × (7 ÷ 12) × 10 = 21.39 cu ft.
- Cubic yards: 21.39 ÷ 27 = 0.79 cu yd, or 36 bags of 80 lb.
Concrete by number of steps (4 ft wide, 7 in rise, 11 in tread)
| Steps | Cu ft | Cu yd | 80 lb bags |
|---|---|---|---|
| 2 | 6.42 | 0.24 | 11 |
| 3 | 12.83 | 0.48 | 22 |
| 4 | 21.39 | 0.79 | 36 |
| 5 | 32.08 | 1.19 | 54 |
| 6 | 44.92 | 1.66 | 75 |
This assumes solid steps on a prepared base. Steps against a house often need a footing and may be formed with a gravel fill core to save concrete; add the footing and subtract the fill if your design has them. Use the stair calculator to set the rise and tread so they meet your local code.
Questions
How much concrete for 3 steps?
About 0.48 cu yd for 4 ft wide steps with a 7 in rise and 11 in tread.
Should I add waste?
Ordering 5–10% extra is common to cover uneven ground and spills.
What rise and tread should I use?
Many residential codes allow a maximum rise of about 7¾ in and a minimum tread of 10 in; check your local code.
Sources
- QUIKRETE Concrete Mix (No. 1101) data sheet, QUIKRETE.
Used for: Bag yields of 0.60, 0.45 and 0.30 cu ft.