Concrete Steps Calculator
Calculate concrete for solid poured steps from the number of steps, riser height, tread depth and width. Get cubic yards, cubic feet and bags of mix to buy.
By CalcBuilt Editorial TeamUpdated September 9, 2026Formulas checked against manufacturer specs, see how we calculate.
Results
- Concrete needed
- 0.52 cu yd
- 14.1 cu ft including 10% waste
- Without waste
- 12.8 cu ft
- Solid steps, 3 risers
- 80 lb bags to buy
- 24 bags
- Rent a mixer and keep two people batching back to back; a batch that skins over before the next goes down is a cold joint
- Total rise
- 21 in
- 3 risers of 7 in
- Total run
- 33 in
- 3 treads of 11 in
Concrete Steps formula
Step volume (cu ft) = Riser (in) / 12 x Tread (in) / 12 x Width (ft) x (1 + 2 + ... + number of steps)
Platform volume (cu ft) = Steps x Riser (in) / 12 x Platform depth (in) / 12 x Width (ft)
Cubic yards = (Step volume + Platform volume) x (1 + waste %) / 27
Bags = Cubic feet with waste / bag yield (80 lb = 0.60 cu ft, 60 lb = 0.45 cu ft)Worked example
Four steps with 7.5 in risers and 12 in treads, 5 ft wide, with a 24 in landing at the top: one riser by one tread by the width is (7.5 / 12) x (12 / 12) x 5 = 3.125 cubic feet. The four layers count 1 + 2 + 3 + 4 = 10 units, so the steps are 31.25 cubic feet. The landing is 4 x 7.5 / 12 = 2.5 ft tall, 2 ft deep and 5 ft wide, another 25 cubic feet.
Total 56.25 cubic feet. With 10% waste that is 61.9 cubic feet, or 2.29 cubic yards, which would take 104 bags of 80 lb mix. That size job is better ordered as 2.5 yards of ready-mix.
Quick reference
| Steps | Total rise | Cubic feet | Cubic yards | 80 lb bags |
|---|---|---|---|---|
| 1 | 7 in | 2.1 | 0.08 | 4 |
| 2 | 14 in | 6.4 | 0.24 | 11 |
| 3 | 21 in | 12.8 | 0.48 | 22 |
| 4 | 28 in | 21.4 | 0.79 | 36 |
| 5 | 35 in | 32.1 | 1.19 | 54 |
| 6 | 42 in | 44.9 | 1.66 | 75 |
How to calculate concrete for steps
Think of solid steps as a stack of slabs. The top slab is one riser tall and one tread deep. The one under it is one riser tall and two treads deep, and so on down to the bottom slab, which runs the full length of the stair. Multiply riser by tread by width for the smallest slab, then multiply by 1 + 2 + 3 up to the number of steps. If the top step is a landing, add its extra depth as a block the full height of the stair.
Measure the total rise from the finished walk or slab to the door threshold, not from the dirt. A walk poured later at 4 inches leaves the bottom riser 4 inches short and fails the 3/8 inch rule. Divide by a riser height near 7 inches and round to a whole number of steps. All risers must match within 3/8 inch (IRC R311.7.5.1), so adjust every riser rather than making the last step different.
Forming and pouring
Steps against a house bear on a footing below frost depth or on the foundation itself, or they heave and pull away from the wall. Epoxy #4 dowels 6 inches into the foundation at 24 inches on center and put 1/2 inch fiber expansion joint between the steps and the house. Form the risers with 2x8s beveled on the bottom edge so the trowel reaches the whole tread, and set the top of every riser form from one story pole. Brace each form with 2x4 kickers to stakes every 2 feet; wet concrete pushes 150 lb per cubic foot.
For stairs more than a few feet tall, fill the center with compacted gravel or clean rubble and pour only a 6 to 8 inch shell around it. That can cut the concrete by half or more. Order 3,500 psi air-entrained where weathering is severe (IRC Table R402.2) and never add water at the chute; ask the plant for a mid-range water reducer instead. Mix bagged concrete stiff, at a 3 to 4 inch slump, so it holds in the tread forms. Pour from the bottom step up, rodding each riser to remove air pockets, and slope the treads 1/4 inch per foot to drain. Strip the riser forms as soon as the concrete holds its shape to finish the faces.
What this calculator leaves out
The result is concrete only. Add the footing or 4 inch gravel base, #4 dowels and epoxy, form lumber and stakes, expansion joint, and the gravel fill under a tall stair. Four or more risers need a handrail (IRC R311.7.8), and its sleeves or anchors go in before the pour.
On a ready-mix order the ticket adds a short-load fee under 4 to 6 yards, and a fuel or environmental surcharge. Standby runs after the free unload window of about 5 to 7 minutes per yard. Most plants will not dispatch under 2 to 3 yards. A line pump, typically $600 to $1,000 in 2026, is needed when the truck cannot get its 16 foot chute to the forms.
Mistakes that cost money
- Risers that vary more than 3/8 in fail inspection (IRC R311.7.5.1); set every riser form from one story pole, not from the last step.
- An unbraced riser form bulges under 150 lb per cubic foot of concrete; screw 2x4 kickers to stakes every 2 ft on each riser.
- Steps poured on fill with no footing below frost depth heave off the house; bear on undisturbed soil and dowel into the foundation.
- Plain 3,000 psi on exterior steps scales in freeze-thaw; IRC Table R402.2 wants 3,500 psi air-entrained where weathering is severe.
- Four or more risers need a handrail (IRC R311.7.8); set the post sleeves or anchors before the pour, not with a hammer drill after.
- A soupy mix slumps out of the tread forms and the risers sag; mix bagged concrete stiff, 3 to 4 in slump, and rod it.
Key facts
- The IRC limits risers to 7.75 in and requires treads at least 10 in deep, with no more than 3/8 in variation between steps.
- Three 7 x 11 in steps 4 ft wide use about 12.8 cubic feet of concrete, roughly 22 bags of 80 lb mix before waste.
- Concrete for steps grows quickly: six steps use about 3.5 times as much as three steps of the same size.
- Two risers plus one tread should total 24 to 25 in for a comfortable stair.
- Solid steps taller than about 3 ft are often poured over a fill of compacted gravel or rubble to save concrete.
- Exterior steps in a severe weathering region need 3,500 psi air-entrained concrete under IRC Table R402.2.
Frequently asked questions
How much concrete do I need for 3 steps?
Three 7 in by 11 in steps 4 ft wide need about 12.8 cubic feet, or 0.48 cubic yards. With 10% waste, plan on 24 bags of 80 lb mix.
How many bags of concrete for 4 steps?
Four 7 x 11 in steps 4 ft wide are about 21.4 cubic feet. That is 36 bags of 80 lb mix or 48 bags of 60 lb mix before waste.
Should I mix bags or order ready-mix for steps?
Three or four steps 4 ft wide are about half a yard. That is 24 to 36 bags of 80 lb mix and an afternoon with a rented mixer and two people batching. A truck for half a yard pays the full short-load fee, and many plants will not dispatch under 2 to 3 yards. Past about 40 bags, or any stair with a landing, order ready-mix rounded up to the next quarter yard.
Do concrete steps need a footing?
Yes. Steps against a house should bear on a footing below the frost line or on the foundation itself, otherwise frost heave will lift and tilt them.
Sources and references
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The usual order for a concrete & masonry project. See all concrete & masonry calculators.
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Results are estimates based on standard formulas and typical product specifications. Confirm quantities with your supplier and local code before ordering.