Concrete Steps Calculator
Work out the concrete for a set of solid steps that rest on the ground, such as front-door or patio steps, including an optional landing at the top. Enter the number of steps, the rise and tread of each, the width, and the landing depth.
How to use the concrete steps calculator
- Keep Steps selected and enter the number of steps (risers), not counting the landing.
- Enter the rise per step and the tread depth in inches. Homes are limited to a 7¾ in rise and need at least a 10 in tread (IRC).
- Enter the width of the steps in feet.
- If there is a landing at the top, enter its depth from front to back in inches; 0 means no landing.
- Read the cubic yards and bags. The calculator warns you if the rise or tread breaks the IRC limits.
How concrete steps are calculated
Solid steps on grade are a staircase of blocks that each reach down to the ground. Seen from the side, step 1 is one rise tall, step 2 is two rises tall, and so on. So the volume is:
Volume = width × tread × rise × (1 + 2 + … + n)
with tread and rise converted from inches to feet. A top landing adds a block as deep as the landing and as tall as all the steps together: width × landing depth × n × rise. Divide by 27 for cubic yards, add waste and divide by the bag yield (0.60 ft³ for an 80 lb bag) to count bags.
Worked example: 4 steps with a 36 in landing
This is the staircase loaded above: 4 steps, 7 in rise, 11 in tread, 4 ft wide, with a 36 in deep landing at the top.
- Steps: 4 × (11 ÷ 12) × (7 ÷ 12) × (1 + 2 + 3 + 4) = 4 × 0.917 × 0.583 × 10 = 21.4 ft³.
- Landing: 4 × (36 ÷ 12) × (4 × 7 ÷ 12) = 4 × 3 × 2.33 = 28 ft³.
- Total: 49.4 ft³, or 1.83 yd³. Add 10%: 2.01 yd³.
- Bags: 54.33 ft³ ÷ 0.60, rounded up to 91 bags of 80 lb mix.
The landing holds more concrete than the steps themselves. That is why many builders fill the inside of large steps with compacted gravel or clean rubble, as long as the concrete shell stays thick enough.
Step dimensions and the building code
The International Residential Code (R311.7) sets the limits for steps at homes: a maximum riser of 7¾ in and a minimum tread of 10 in, and the risers in one flight shouldn't differ by more than ⅜ in. A handrail is required once there are four or more risers. Most exterior doors also need a landing at least 36 in deep in the direction of travel.
Comfortable outdoor steps often use a slightly lower rise and a deeper tread, for example 6–7 in by 12–14 in. Pick your dimensions first, then use the calculator to see how the concrete changes: a deeper tread adds volume to every step.
Concrete for 1 to 6 solid steps, with and without a top platform
| Steps (7 in rise, 11 in tread, 4 ft wide) | Total height | yd³ | 80 lb bags (+10%) | With 36 in top platform: yd³ | Platform: 80 lb bags |
|---|---|---|---|---|---|
| 1 step | 7 in | 0.08 | 4 | 0.34 | 17 |
| 2 steps | 14 in | 0.24 | 12 | 0.76 | 38 |
| 3 steps | 21 in | 0.48 | 24 | 1.25 | 63 |
| 4 steps | 28 in | 0.79 | 40 | 1.83 | 91 |
| 5 steps | 35 in | 1.19 | 59 | 2.48 | 123 |
| 6 steps | 42 in | 1.66 | 83 | 3.22 | 160 |
Solid steps resting on the ground (no fill inside). Cubic yards without waste. Filling the core with compacted gravel or rubble cuts the concrete needed.
Tips for building concrete steps
- Measure the total rise first. Measure from the ground to the top of the landing or door sill, then divide by the number of steps so every riser is equal.
- Slope the treads slightly. A small fall toward the front of each tread lets water drain off, which matters in freezing weather.
- Brace the forms well. Step forms hold a lot of weight. Stake and brace the riser boards, and bevel their bottom edge so you can finish the full tread.
- Fill the core on big steps. Compacted gravel inside a large landing can cut the concrete by a third or more; ask your building department about minimum shell thickness and reinforcement.
- Pour from the top down. Fill the landing and top step first, then work down, so concrete doesn't push out under the lower riser forms.
Frequently asked questions
How much concrete do I need for 3 steps?
Three solid steps with a 7 in rise, 11 in tread and 4 ft width hold 12.83 ft³, or 0.475 yd³. With 10% waste that is 24 bags of 80 lb mix. A 36 in landing on top adds about another 0.78 yd³.
How many bags of concrete for steps?
Work out the volume with the formula above and divide by 0.60 ft³ per 80 lb bag. The table gives totals for 1–6 steps; a 4-step set without a landing needs about 40 bags of 80 lb mix, or 91 bags with a 36 in landing.
What is the maximum step height for outdoor stairs?
For homes, the IRC allows a riser of up to 7¾ in and requires treads of at least 10 in. Your local code may differ, so check before building.
Can I fill concrete steps with gravel or rubble?
Yes, many builders fill the core of large steps or landings with compacted gravel or clean broken concrete to save material. Leave a solid concrete shell of several inches on all faces; your building department can tell you the minimum.
Do concrete steps need a handrail?
Under the IRC, a handrail is required on stairs with four or more risers. Plan for the post anchors before you pour.
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