Concrete steps cost & volume calculator
Work out both the concrete volume (cubic feet, cubic yards and bags) and the installed cost of a poured concrete staircase from the number of steps, riser, tread, width and your price per step.
Calculator
4 steps (7" riser, 11" tread, 4 ft wide) is about 21.4 cu ft of concrete (36 bags) and, at $150.00/step, roughly $600.00 installed. Confirm yield on your bag and order a little extra.
Formula
A stacked staircase is a set of nested prisms: the bottom step is a full-height block, each step above it one riser shorter. Summing them gives a tidy closed form:
volume (cu ft) = width × riser_ft × tread_ft × [n × (n + 1) ÷ 2]
Then cubic yards = cu ft ÷ 27 and bags = ceil(cu ft ÷ bag yield), where an 80 lb bag yields about 0.60 ft³, a 60 lb about 0.45 ft³ and a 40 lb about 0.30 ft³. Cost is simply steps × $/step.
Worked example
4 steps, a 7" riser (0.583 ft), an 11" tread (0.917 ft) and a 4 ft width. The prism count is 4 × 5 ÷ 2 = 10, so:
4 × 0.583 × 0.917 × 10 ≈ 21.4 cu ft = 0.79 yd³
At 0.60 ft³ per 80 lb bag that is ceil(21.4 ÷ 0.60) = 36 bags. At $150/step the installed cost is 4 × 150 = $600.
Pouring concrete steps: volume and cost
Concrete steps are one of the trickier pours to estimate because the shape is not a simple slab. Treating the staircase as a stack of prisms — each step a rectangular block one riser shorter than the one below — turns it into a single formula, and the n(n+1)/2 term is just the sum of 1 through n.
Riser and tread
A comfortable residential stair uses a riser around 7 inches and a tread around 11 inches; deeper treads and shorter risers feel easier underfoot but use more concrete. Because both feed the volume directly, changing them changes your bag count — the calculator shows the effect instantly.
Solid vs. hollow
This formula assumes a solid poured staircase, which is the conservative, buy-enough answer. Many crews save concrete by building over a compacted fill or a formed void, so your actual yield can be lower. Always confirm the yield on your bag and order a little extra — 5–10% — for spillage and over-excavation; running short mid-pour is far worse than having a bag left over.
Bag size and small pours
For a modest set of steps, bagged mix is often the practical choice; 80 lb bags mean fewer to haul, while 40 or 60 lb bags are easier to lift. Switch the bag size to see how many you need of each. If the volume climbs past a couple of cubic yards, compare against ready-mix with the ready-mix vs bags tool, and price the yardage with the concrete cost per yard calculator.
The cost side
The installed cost here is priced per step, which is how many contractors quote a self-contained stoop or stair. That per-step figure bundles forming, the concrete, finishing and often a railing anchor, so it is more than just the material. Enter the number from your own quote; the volume output stands on its own if you are pouring the steps yourself.
Two notices, on purpose
This tool shows both a planning-estimate note (for the cost) and a quantity/coverage note (for the volume and bags), because it produces both kinds of answer. The cost is a planning estimate, not a bid; the bag count is a starting quantity to confirm against your product and pad for waste. Neither is a structural design — a licensed engineer sizes load-bearing concrete.
Railings and finish
Most jurisdictions require a graspable handrail once a stair rises beyond a set number of risers, and outdoor concrete steps are usually given a broom or textured finish for grip when wet. Neither the railing nor the finish is in the volume math, but both belong in the per-step price you enter — a stair quoted with a railing anchor and a non-slip finish costs more per step than a bare pour, so make sure the figure you use reflects the steps you actually want built.
Frequently asked questions
How many bags of concrete do I need for steps?
Compute the volume with the formula above, then divide by the bag yield: about 0.60 ft³ for an 80 lb bag, 0.45 for 60 lb and 0.30 for 40 lb, rounding up. The four-step example needs about 36 bags of 80 lb mix for 21.4 cubic feet.
What is a comfortable riser and tread?
A 7-inch riser with an 11-inch tread is a common, comfortable combination for residential stairs. Deeper treads and shorter risers feel easier but use more concrete.
Does the calculator assume solid steps?
Yes — it assumes a fully solid pour, which is the buy-enough answer. If your steps are built over compacted fill or a formed void, your actual concrete use will be lower, so treat the result as a safe maximum.
Should I order a little extra?
Always. Confirm the yield on your bag and add 5–10% for spillage, uneven forms and over-excavation. Running short mid-pour causes a cold joint; a spare bag does not.
How is the cost figured?
As number of steps × your price per step. That per-step price, from your own quote, bundles forming, concrete and finishing. It is a planning estimate, not a bid.