Know the parts: rise, run and landing
- Rise is the vertical height of one step.
- Run (tread depth) is the horizontal depth of one step, front to back.
- Width is side to side.
- Landing (platform) is the flat area at the top, often in front of a door.
For a set of steps from a patio to a door, measure the total height from the lower surface to the threshold. Divide by your target rise to get the number of steps. Then adjust the rise so every step is the same height.
Residential code limits
The International Residential Code (R311.7.5) limits riser height to 7¾ in maximum and requires a tread depth of at least 10 in. Within one flight, risers and treads can't vary by more than ⅜ in. Local amendments differ, and exterior steps may also need a landing of a minimum size at the door, plus handrails, depending on height. Check with your building department.
| Total height | Steps at ≤7¾ in | Actual rise per step |
|---|---|---|
| 14 in | 2 | 7.00 in |
| 21 in | 3 | 7.00 in |
| 28 in | 4 | 7.00 in |
| 30 in | 4 | 7.50 in |
| 36 in | 5 | 7.20 in |
| Total height | Steps at ≤19.7 cm (the IRC limit) | Actual rise per step |
|---|---|---|
| 35 cm | 2 | 17.5 cm |
| 55 cm | 3 | 18.3 cm |
| 70 cm | 4 | 17.5 cm |
| 75 cm | 4 | 18.8 cm |
| 90 cm | 5 | 18.0 cm |
How the volume is calculated
The calculator treats the steps as a stack of solid blocks. Step 1 is one rise tall, step 2 is two rises tall, and so on, each one run deep and the full width wide:
Volume = width × run × rise × (1 + 2 + … + n), plus width × landing depth × total height if you add a landing.
For 3 steps at 7 in rise and 11 in run, 4 ft wide: 4 × 0.917 × 0.583 × 6 = 12.83 ft³.
A note on other calculators: some treat the top step as the landing, or count one fewer step-height, so their result can be noticeably lower for the same inputs. When we compared outputs in October 2026, one popular calculator returned about half our figure for this exact example. Both methods are internally consistent; they're just answering slightly different questions. If you'll pour a separate landing slab, enter 0 for landing depth here and size the landing with the slab calculator.
Worked examples
Back door: 3 steps, 4 ft wide, 7 in rise, 11 in runBack door: 3 steps, 1.22 m wide, 17.8 cm rise, 27.9 cm run
I know The number of steps · Total height to climb 21 in · Number of steps 3 · Stair width 4 ft · Rise per step 7 in · Run per step 11 in · Top landing depth 0 in · Waste / overage 10 %I know The number of steps · Total height to climb 53.3 cm · Number of steps 3 · Stair width 1.22 m · Rise per step 17.8 cm · Run per step 27.9 cm · Top landing depth 0 cm · Waste / overage 10 %
- Concrete volume: 0.52 yd³ (14.1 ft³)Concrete volume: 0.4 m³ (400 L)
- 80 lb bags: 2440 kg bags: 22
Front entry: 4 steps, 5 ft wide, 7 in rise, 11 in run, 48 in landingFront entry: 4 steps, 1.52 m wide, 17.8 cm rise, 27.9 cm run, 122 cm landing
I know The number of steps · Total height to climb 21 in · Number of steps 4 · Stair width 5 ft · Rise per step 7 in · Run per step 11 in · Top landing depth 48 in · Waste / overage 10 %I know The number of steps · Total height to climb 53.3 cm · Number of steps 4 · Stair width 1.52 m · Rise per step 17.8 cm · Run per step 27.9 cm · Top landing depth 121.9 cm · Waste / overage 10 %
- Concrete volume: 2.99 yd³ (80.7 ft³)Concrete volume: 2.29 m³
- 80 lb bags: 13540 kg bags: 123
The landing makes up a large share of the volume. Consider filling its core with compacted gravel or broken concrete to save material.
Garden steps: 2 steps, 3 ft wide, 6 in rise, 14 in runGarden steps: 2 steps, 0.91 m wide, 15.2 cm rise, 35.6 cm run
I know The number of steps · Total height to climb 21 in · Number of steps 2 · Stair width 3 ft · Rise per step 6 in · Run per step 14 in · Top landing depth 0 in · Waste / overage 10 %I know The number of steps · Total height to climb 53.3 cm · Number of steps 2 · Stair width 0.91 m · Rise per step 15.2 cm · Run per step 35.6 cm · Top landing depth 0 cm · Waste / overage 10 %
- Concrete volume: 0.21 yd³ (5.8 ft³)Concrete volume: 0.164 m³ (164 L)
- 80 lb bags: 1040 kg bags: 9
- 60 lb bags: 1325 kg bags: 14
Saving concrete on tall steps
Solid steps add up quickly: each extra step adds a full block under every tread above it. Builders often fill the interior with compacted gravel, clean rubble or a block core, then pour a shell 4–6 in thick. If you do, estimate the shell by subtracting the fill volume, or calculate the tread slabs and riser walls separately. Check with your inspector whether a solid pour or a footing is required where steps attach to a foundation.
Forming and pouring tips
- Bevel the bottom edge of each riser form board so you can trowel the full tread.
- Slope each tread slightly toward its front edge so water drains off. Your local inspector can tell you what pitch they expect.
- Brace the riser forms well. Concrete pressure pushes them outward.
- Pour from the bottom step up, and wait until the concrete stiffens a little before finishing the higher treads.
- Wet concrete causes chemical burns. Wear gloves, eye protection and boots (OSHA).
Measuring an existing opening
To build steps up to a door or deck, measure the total rise from the finished lower surface (the patio or walkway) straight up to the top surface (the threshold or deck). Use a level and a straight board if the ground slopes away. Measure the available run too: the horizontal space you have in front of the door. Your number of treads × tread depth, plus any landing, has to fit in that space. If it doesn't, you'll need a landing that turns, or a different layout.
Checked against
Each case below is re-run against the calculator by our automated test suite.
| Case | Our result | Checked against | Result |
|---|---|---|---|
| 3 steps, 4 ft wide, 7 in rise, 11 in run, no waste: volume | 0.48 yd³ (12.8 ft³) | calculator.net concrete calculator | Differs: calculator.net gives about half, because it counts one fewer step height. See “How the formula works” above. |
| Case | Our result | Checked against | Result |
|---|---|---|---|
| 3 steps, 1.22 m wide, 17.8 cm rise, 27.9 cm run, no waste: volume | 0.363 m³ (363 L) | calculator.net concrete calculator | Differs: calculator.net gives about half, because it counts one fewer step height. See “How the formula works” above. |
Frequently asked questions
Why is my result different from another calculator?
Usually because of the top-step convention. Some tools subtract one step and treat the top as a landing. Enter 0 for the landing here and compare like with like.
How many bags of concrete for 3 steps?
For 3 steps, 4 ft wide with a 7 in rise and 11 in run, about 12.8 ft³: 22 bags of 80 lb mix before waste, 24 with 10%.
What is the maximum step height?
The IRC limits risers to 7¾ in and requires treads of at least 10 in. Local codes can differ.
Do concrete steps need a footing?
Often, especially when attached to a house or in frost areas. Ask your building department.
Sources & assumptions
The results are planning estimates, and the cost figures only use prices you enter. Product yields, densities and coverage rates vary, so check the label or ask your supplier, and follow local codes. Figures marked "approximate" or "rule of thumb" are general practice, not exact standards.
- International Residential Code R311.7.5 (stair risers and treads)
- Quikrete Concrete Mix data sheet (bag yields, minimum thickness)
- OSHA: Preventing Skin Problems from Working with Portland Cement
See how we calculate and test our formulas and the changelog. Last updated 2026-10-08.
Reviewed by the MaterialWhiz Editorial Team. This estimate uses the assumptions shown in the calculator. Review the result against your supplier's product coverage and site conditions. Last reviewed: October 10, 2026. See how we calculate · Report a correction.