Concrete Stairs Calculator
Pouring a set of steps? Enter the number of steps, the rise, the run, and the width to get the concrete you need — in cubic yards for ready-mix, or 40, 60, and 80-lb bags.
Free · no sign-up ·
You need · incl. +10% extra
- 40-lb bags
- 89
- Cubic feet
- 26.5 ft³
- Cubic meters
- 0.75 m³
- Exact volume
- 0.89 yd³
Use cubic yards to order ready-mix by the truck; bag counts for a smaller hand-mixed pour. Bag yields: 80-lb ≈ 0.6 ft³, 60-lb ≈ 0.45 ft³, 40-lb ≈ 0.3 ft³.
Order about 10% extra — you can’t pause a pour to mix more, and the subgrade is never perfectly level. Past ~½ yard, ready-mix is usually cheaper and far less work than bags.
The formula
For solid stairs on grade, Volume = Width × Run × Rise × n(n+1)/2, where n is the number of steps. Convert to cubic yards (1 yd³ = 27 ft³).
How to estimate concrete for a concrete stairs
Concrete stairs take more material than people expect, because each step sits on the fill of all the steps below it. The volume of a solid flight poured on grade is the stair width times the run times the rise times n(n+1)/2, where n is the number of steps — that triangular-number factor is why doubling the steps more than doubles the concrete. The calculator does the arithmetic from your step count, rise, run, and width.
Use comfortable, code-friendly step dimensions: a rise of about 7 inches and a run (tread depth) of about 11 inches is the classic, with most codes capping the rise around 7.75 inches and setting a minimum run. Keep every step in a flight the same rise and run — uneven steps are both a trip hazard and a code failure. Enter your actual rise and run so the volume matches what you will build.
This estimate assumes solid stairs cast on a compacted base or sloped grade, with no hollow core or separate landing. If your stairs include a top landing or platform, size that separately as a slab and add it. Order about 10% extra concrete, set and brace the forms well, and remember stairs usually need a footing at the base and rebar — confirm with your local code.
Frequently asked questions
How much concrete do I need for stairs?+
For solid stairs on grade, the volume is width × run × rise × n(n+1)/2, where n is the number of steps. A 5-step flight at 7-inch rise, 11-inch run, and 3 feet wide is about 24 cubic feet, or 0.9 cubic yards. Enter your numbers above for an exact figure.
How do I calculate concrete for steps?+
Measure the rise and run of one step, the stair width, and count the steps, then the calculator applies the solid-stairs formula and returns cubic yards and bag counts. Each step adds the fill of all the steps below it, so the total grows quickly.
What is a good rise and run for stairs?+
About a 7-inch rise and an 11-inch run (tread depth) is the comfortable standard. Most building codes cap the rise near 7.75 inches and set a minimum run, and require every step in a flight to be the same. Check your local code for exact limits.
How many bags of concrete for steps?+
An 80-lb bag yields about 0.6 cubic feet. A 5-step, 3-foot-wide flight (≈24 ft³) needs about 44 eighty-pound bags with waste — right at the point where ready-mix starts to make sense.
Why do stairs need so much concrete?+
Because the steps stack: the top step sits on the fill of every step beneath it, so the volume follows n(n+1)/2, not just the number of steps. Doubling from 5 to 10 steps more than doubles the concrete — the calculator captures this.
Do concrete stairs need a footing?+
Usually yes — a footing at the base of the stairs, below the frost line in cold climates, keeps them from settling or heaving. Size it with the concrete footing calculator and confirm the requirement with your local code.
Should I include a landing in the calculation?+
This calculator estimates the stepped flight only. If your stairs have a top landing or platform, size it separately as a concrete slab (width × depth × thickness) and add it to the total.
Do concrete stairs need rebar?+
Most poured stairs carry rebar to tie them together and to the footing, sized per code or an engineer. The calculator estimates concrete volume, not reinforcement.
How much extra concrete should I order for stairs?+
About 10%. Step forms are fiddly and some concrete is lost to spillage and over-fill, so order a little over. The calculator includes an adjustable overage.
Is this concrete stairs calculator free?+
Yes — free, no sign-up, and it runs entirely in your browser, so nothing you enter is stored or sent anywhere.