Concrete Steps Calculator: How Much Concrete for Steps?
Steps are a stack of boxes, each one a riser taller than the last — which is why the concrete adds up faster than most people expect. Enter your step count and dimensions for cubic yards and bag counts, updated live. The defaults are a typical 4-step porch stoop.
Before waste: 22.9 ft³ (0.85 yd³). Waste is added on top so you don't run short mid-pour.
Bags to buy (with waste)
Steps Bag Table: 2 to 6 Steps, 4 ft Wide
All rows use the standard residential step: 11 in tread, 7.5 in riser, 4 ft wide. Exact counts are the mathematical minimum, rounded up; the "with waste" counts multiply the volume by 1.10 first. Yields: 80 lb bag = 0.60 ft³, 60 lb = 0.45 ft³.
| Steps | Total rise | Volume | 80 lb exact | 80 lb +10% | 60 lb exact | 60 lb +10% |
|---|---|---|---|---|---|---|
| 2 | 15 in | 6.9 ft³ (0.25 yd³) | 12 | 13 | 16 | 17 |
| 3 | 22.5 in | 13.8 ft³ (0.51 yd³) | 23 | 26 | 31 | 34 |
| 4 | 30 in | 22.9 ft³ (0.85 yd³) | 39 | 43 | 51 | 57 |
| 5 | 37.5 in | 34.4 ft³ (1.27 yd³) | 58 | 64 | 77 | 85 |
| 6 | 45 in | 48.1 ft³ (1.78 yd³) | 81 | 89 | 107 | 118 |
Notice the pattern: each added step costs more concrete than the one before it, because every new step is a full riser taller along its whole run. Going from 4 steps to 6 more than doubles the volume, from 0.85 yd³ to 1.78 yd³ — and pushes the pour well past the point where a ready-mix truck beats bags on both price and labor.
How the Math Works
Look at a staircase from the side. Each step is a box one tread deep, and the boxes stack: the bottom step is 1 riser tall, the next is 2 risers, and so on up to the top step at the full height. Add the boxes up and the profile is a staircase triangle of 1 + 2 + … + n riser-heights — which sums to n(n+1) ÷ 2.
Volume (ft³) = width × tread (ft) × riser (ft) × n(n+1) ÷ 2 · Bags = ft³ ÷ yield, rounded up
Worked example, the 4-step stoop above: 4 ft wide, 11 in tread (0.917 ft), 7.5 in riser (0.625 ft), n = 4, so the multiplier is 4 × 5 ÷ 2 = 10. Volume = 4 × 0.917 × 0.625 × 10 = 22.9 ft³, or 22.9 ÷ 27 = 0.85 yd³. Bags of 80 lb mix: 22.9 ÷ 0.60 = 38.2, so 39 bags exact — or 43 with the 10% cushion.
- Measure the total rise first. Ground to landing (or porch floor), in inches. Divide by your riser height to get the step count, then adjust the riser so every step comes out equal — uneven risers are a trip hazard and a code failure. Total rise of 30 in at a 7.5 in riser is exactly 4 steps.
- Pick a legal, comfortable step. Residential code typically caps risers at about 7¾ in and requires treads at least 10 in deep; 7–7.5 in risers with 11 in treads is the comfortable standard. Confirm your local numbers before forming.
- Figure the landing separately. This calculator covers the steps themselves. A poured landing or top pad is just a slab — add it with the main calculator, and figure the gravel base under both with the gravel calculator.
One assumption to know about: this math treats the steps as solid, which is how most small stoops and porch steps are actually poured — formed against grade or a sloped fill. If your steps are formed hollow over a sloped stringer, you will use less; solid is the safe number to order against.
Pouring a Slab or Landing Too?
Steps usually land on, or lead to, a slab. Figure that pour with the main calculator, or use the size guides: 10×10 slab, 12×12 slab, 12×20 slab.
Concrete Steps FAQ
How many bags of concrete for 4 steps?
For standard 4 ft wide steps with an 11 in tread and 7.5 in riser: 43 bags of 80 lb mix to buy (39 exact, plus 10% waste), or 57 bags of 60 lb. The pour is 22.9 ft³, about 0.85 yd³ — right at the size where bags and a small ready-mix order cost about the same, so labor usually makes the call.
How do I figure out how many steps I need?
Measure the total rise — the vertical distance from the ground (or lower slab) to the landing or porch floor — and divide by your riser height. A 30 in rise at 7.5 in per riser is 4 steps. Then re-divide the total rise by the step count so every riser is exactly equal: 30 ÷ 4 = 7.5 in each. Never let one step absorb the leftover fraction; uneven risers are the classic trip hazard.
What is a standard step size?
Residential steps are typically a 7 to 7.5 in riser with a 10 to 11 in tread. Building code in most places caps the riser at about 7¾ in and sets the minimum tread at 10 in, and all risers in a flight must be nearly identical. Wider treads and shorter risers feel more comfortable, especially on exterior steps that get used with armfuls of groceries.
Do concrete steps need a footing or base?
Small stoops are commonly poured over a compacted gravel base (figure it with the gravel calculator), and in frost country the base or footing under the bottom step should reach below the frost line so the flight does not heave and pull away from the house. Steps attached to a foundation are often doweled into it. Local code governs — check before you form.
Estimates Only
Results are planning estimates for solid poured steps. Actual concrete needs vary with form accuracy, ground conditions, and product yield. Bag yields follow manufacturer figures for standard mixes; your product may differ slightly. Always order a little extra — running short mid-pour creates a weak cold joint. Riser and tread limits are set by local building code; confirm them, and for structural work consult a licensed professional.