Concrete Steps Calculator
A {width} ft wide staircase with {steps} steps, a {rise} in rise and {run} in run, needs about {bags} {bag}-lb bags of concrete — {cubicYards} cubic yards if you order ready-mix.
Concrete needed for common step configurations
| Width | Steps | Rise | Run | Cubic yards | 50-lb bags | 60-lb bags | 80-lb bags |
|---|---|---|---|---|---|---|---|
| 3 ft | 3 | 7 in | 11 in | 0.39 | 29 | 24 | 18 |
| 4 ft | 3 | 7 in | 11 in | 0.52 | 38 | 32 | 24 |
| 4 ft | 4 | 7 in | 11 in | 0.87 | 63 | 53 | 40 |
| 4 ft | 5 | 7 in | 11 in | 1.31 | 95 | 79 | 59 |
| 5 ft | 4 | 6 in | 12 in | 1.02 | 74 | 62 | 46 |
| 3 ft | 5 | 7 in | 11 in | 0.98 | 71 | 59 | 45 |
Full solid-fill volume (stacked-rectangle method), includes 10% extra. Subtract any gravel or block fill you plan to use under the steps.
How the math works
Steps are calculated with the stacked-rectangle method: each step is treated as its own full-depth rectangular block reaching all the way down to the ground, and the volumes are added together. The bottom step is the shallowest block; each step above it is one more rise taller.
total = sum of step 1 through step "count"
bags = (total cubic feet × 1.10) ÷ bag yield
This method assumes solid concrete all the way down, which is simplest to calculate and matches how many small residential step pours are actually done. If you're filling underneath with compacted gravel or masonry block to save concrete, treat this number as the upper bound and subtract your fill volume.
What building codes typically require
| Requirement | Common value |
|---|---|
| Maximum riser height | 7¾ in |
| Minimum tread depth | 10 in |
| Riser/tread uniformity | Largest can't exceed smallest by more than ⅜ in |
| Minimum clear width | 36 in |
| Minimum headroom | 6 ft 8 in |
| Handrail required | At 4 or more risers |
| Handrail height | 34–38 in above the nosing line |
| Max rise per flight before a landing | 12 ft |
These are widely cited residential code minimums (IRC-style stairway provisions) — always confirm the specifics against your locally adopted code edition and any amendments before finalizing a design.
A bottom landing is commonly required to be at least as deep as the stair is wide, with 36 inches as a floor — not a fixed number. A 42-inch-wide stair needs a 42-inch-deep landing, not 36. Build a generous 48-inch-wide entry stair and you owe a 48-inch-deep landing, which meaningfully changes the concrete volume for that landing pad. The landing surface also has to be firm and level — bare soil doesn't qualify — and shouldn't slope more than about 2% (¼ inch per foot) for drainage. If your stair is wider than 36 inches, size the landing to match the stair width, not the code floor.
Legal isn't always comfortable
| Rise + run | Sum | Feel |
|---|---|---|
| 7 in + 11 in | 18 | Widely considered the most comfortable combination |
| 7¾ in + 10 in | 17.75 | Legal, but noticeably steep on the way down |
Both combinations can satisfy code minimums, but they don't feel the same underfoot — and a concrete stair is permanent. If you have room to work with, 7-and-11 is the more forgiving choice.
Hollow-core vs. solid-fill
Voiding the interior of a step with compacted fill or void forms saves real concrete and real weight, and it's standard practice in precast steps. Cast in place, though, it's only a safe option if the shell is thick enough and properly reinforced — a hollow step is a small structure spanning a void, not just a smaller pile of concrete, and a shell that's too thin or unreinforced can crack and collapse under repeated foot traffic. Solid-fill is simpler to form and carries no such risk, at the cost of more material and more weight — which matters directly at a door landing, where the load lands on backfill that's often the least-compacted soil on the whole site.
Before you buy
- Keep rise and run consistent across every step — inconsistent steps are a common trip hazard and a common code violation.
- Consider a gravel or compacted-fill core under the steps instead of solid concrete for anything more than 2 or 3 steps; it saves material and reduces weight on the footing below.
- Pour a proper footing under the steps, especially where they meet a door threshold or a load-bearing structure — see the footing calculator.
- Use rebar or wire mesh; steps take repeated point loads that plain unreinforced concrete handles poorly over time.
- Include a landing at the top if the steps lead to a door — check your local code for minimum landing size.
Common questions
How much concrete do I need for outdoor steps?
A 4 ft wide staircase with 3 steps, a 7-inch rise and an 11-inch run needs about 0.52 cubic yards of concrete, or 24 80-lb bags. Volume grows with each additional step since every step sits on top of full-depth concrete down to grade.
What's a comfortable rise and run for steps?
A common residential comfort rule is a 7-inch rise with an 11-inch run, and most codes cap maximum rise around 7.75 inches with a minimum run around 10 inches. Consistent rise and run across every step matters more for safety than the exact numbers.
Why does this calculator's volume seem like a lot for just steps?
Because it uses the stacked-rectangle method: each step is treated as a full-depth block reaching all the way down to the ground, not a hollow shell. That's the volume of solid poured steps; if you're building over a solid, compacted base or block backfill, some of that volume is replaced by fill instead of concrete.
Do concrete steps need rebar?
Yes, for anything more than a single low step. Steps typically use rebar or wire mesh to resist cracking from the repeated point loads of foot traffic and freeze-thaw cycling.
Should I fill under the steps with gravel or compacted fill instead of solid concrete?
Many installers do, to save concrete and reduce weight — a compacted gravel or masonry block fill under the steps, with only the top few inches poured solid. This calculator gives the full solid-fill volume as a starting point; subtract your fill volume if you're using a hollow-core method.