Concrete Stairs Calculator
Short answer: 4 steps at 7 in risers, 11 in treads and 4 ft wide need about 0.79 cubic yards (0.87 with 10% waste). Enter your steps below.
Calculate your steps
How the calculation works
Each step is treated as a solid rectangular block stacked on the one below: the bottom step is one riser high, the next two, and so on. Volume = width × riser × tread × (1 + 2 + … + steps), which is width × riser × tread × steps × (steps + 1) ÷ 2, all converted to feet.
Worked example: 4 steps, 7 in risers, 11 in treads, 4 ft wide = 4 × (7 ÷ 12) × (11 ÷ 12) × 10 = 21.39 cu ft = 0.79 cubic yards, or 0.87 with 10% waste.
Typical step sizes
| Steps | At 7 in riser, 11 in tread, 4 ft wide |
|---|---|
| 3 steps | 0.48 cubic yards · 24 × 80 lb bags (with 10% waste: 0.52 yd) |
| 4 steps | 0.79 cubic yards · 40 × 80 lb bags (with 10% waste: 0.87 yd) |
| 5 steps | 1.19 cubic yards · 59 × 80 lb bags (with 10% waste: 1.31 yd) |
| 6 steps | 1.66 cubic yards · 83 × 80 lb bags (with 10% waste: 1.83 yd) |
Volumes are net (before waste). Bag counts use the 0.60 cu ft yield per 80 lb bag, rounded up, and are shown from the order volume.
Frequently asked questions
How much concrete do I need for 4 steps?
At 7 inch risers, 11 inch treads and 4 ft wide: 0.79 cubic yards net, 0.87 with 10% waste — about 40 × 80 lb bags.
How do you calculate concrete for stairs?
Treat each step as a stacked block: volume = width × riser × tread × steps × (steps + 1) ÷ 2, with all dimensions in feet, then add waste.
What is a standard step riser and tread?
Typical residential practice is about a 7 inch riser and an 11 inch tread, but maximum riser and minimum tread are set by local code — check before pouring.