Calculate how much concrete your steps need in cubic yards, bags and cost from rise, run, width and number of steps, or lay out steps from a total height.
Concrete Steps Formula
This quantity model treats the steps as a solid stepped block above a level base. It adds one vertical column below each modeled tread, including the uppermost tread or landing. It does not subtract a fill core or design reinforcement, foundations or supports. Confirm the actual geometry; a stair ending at a separate upper floor may have a different tread count. For equal modeled treads with no replacement landing:
V = W * Run * Rise * N * (N + 1) / 2
Variables:
- V is the total volume of concrete for the steps
- W is the step width, measured side to side
- Run is the tread depth of each step, front to back
- Rise is the riser height of each step
- N is the number of modeled risers and solid tread columns, including the top tread or landing
The N * (N + 1) / 2 term comes from stacking those columns. The column under the bottom step is one riser tall, the next is two risers tall, and the column under the top step is N risers tall. When you add a top landing, the top step uses the landing depth in place of the run, so the volume becomes:
V = W * Run * Rise * (N - 1) * N / 2 + W * P * (N * Rise)
where P is the replacement top landing depth. It replaces the last normal tread; it is not an extra slab. Height mode chooses N = ceil(total height / the user-specified maximum riser) and then equal rise = total height / N. The footprint is (N−1) × Run + P, or N × Run without a landing. This is a quantity layout and does not establish stair-code compliance:
N = roundup(Total Height / Max Riser) Rise = Total Height / N
One cubic yard is 46,656 cubic inches or 27 cubic feet. Bag count is the order volume, including overage, divided by actual bag yield and rounded up. The approximate presets of 0.60, 0.45, 0.375 and 0.30 cu ft for 80, 60, 50 and 40 lb bags match QUIKRETE1101’s data sheet. Other products may differ; use custom yield when needed.
Use either known step dimensions or a total height and a maximum riser from the project plan. Length fields allow matching physical values in inches, feet, centimeters, millimeters or meters. Optional fields set replacement landing depth, purchasing overage, bag yield and prices. Material estimates distinguish unrounded ready-mix volume from whole purchased bags; the per-tread solid volume appears in Calculation details.
Concrete Needed for Common Steps
This table lists the concrete volume and 80 lb bag count for typical porch steps built with a 7.5 inch rise and an 11-inch run. Bag counts include a 10 percent waste allowance, the same default the calculator uses.
| Steps | Width | Cubic feet | Cubic yards | 80 lb bags |
|---|---|---|---|---|
| 2 | 3 ft | 5.2 | 0.19 | 10 |
| 3 | 3 ft | 10.3 | 0.38 | 19 |
| 4 | 3 ft | 17.2 | 0.64 | 32 |
| 5 | 3 ft | 25.8 | 0.95 | 48 |
| 3 | 4 ft | 13.8 | 0.51 | 26 |
| 4 | 4 ft | 22.9 | 0.85 | 43 |
| 5 | 4 ft | 34.4 | 1.27 | 64 |
| 6 | 4 ft | 48.1 | 1.78 | 89 |
The next table shows something the total volume hides: where the concrete actually goes. For a flight of five equal steps, this is the share of the total concrete that lands in each step column, counted from the bottom.
| Step (bottom to top) | Share of concrete | Running total |
|---|---|---|
| Step 1 (bottom) | 6.7% | 6.7% |
| Step 2 | 13.3% | 20.0% |
| Step 3 | 20.0% | 40.0% |
| Step 4 | 26.7% | 66.7% |
| Step 5 (top) | 33.3% | 100% |
For equal tread depths without a replacement landing, the top column share is 2 / (N + 1): 50% for 3 modeled steps, 40% for 4, and 33.3% for 5. A different landing depth changes those shares. A fill core can change actual quantity, but it must be part of an appropriate project design; this solid-volume calculator does not determine whether a core, shell thickness or reinforcement is suitable.
Example Problems
Example 1: concrete for three porch steps.
You are pouring 3 solid steps that are 36 inches wide, with a 7.5 inch rise and an 11-inch run, and no landing. Using the formula:
V = 36 * 11 * 7.5 * 3 * 4 / 2 = 17,820 cubic inches, which is 10.3 cubic feet or 0.38 cubic yards. At the default 10 percent waste that rounds up to 19 bags of 80 lb mix, or 18 bags with no waste.
Example 2: design steps from a porch height.
Your porch sits 30 inches above the ground and you want risers no taller than 7.5 inches, with an 11-inch run and a 48-inch width. The tool divides 30 by 7.5 to get 4 risers, each exactly 7.5 inches tall, for a total run of 44 inches. The volume is 48 * 11 * 7.5 * 4 * 5 / 2 = 39,600 cubic inches, or 22.9 cubic feet (0.85 cubic yards). With 10 percent waste that is about 43 bags of 80 lb mix.
Frequently Asked Questions
How much concrete do I need for concrete steps?
It depends on the width, rise, run, and number of steps, because the volume grows quickly as steps stack. One 3 foot wide step with a 7.5 inch rise and an 11-inch run takes about 0.06 cubic yards, three of the same steps take about 0.38 cubic yards, and five take about 0.95 cubic yards. Enter your own dimensions for an exact figure, then add waste before you buy.
Are concrete steps poured solid or hollow?
Steps can use different structural arrangements, including solid blocks, designed construction over fill, and reinforced suspended flights. Their foundation, support and reinforcement requirements depend on the project and cannot be inferred from step height alone. This calculator estimates a solid stepped block and makes no finding that reinforcement is unnecessary.
What rise and run should concrete steps use?
Use riser, tread, landing, handrail, drainage and dimensional-variation requirements applicable to the project’s jurisdiction and occupancy. There is no single universal US riser/tread limit for every stair. Enter the maximum riser specified by your plan; the quantity layout does not verify code compliance, accessibility or safe construction.
