Quick answer: To find concrete for stairs, the volume is width × [ steps × (steps+1) ÷ 2 × riser × run ]. Divide cubic inches by 46,656 for cubic yards, or by 1,728 for cubic feet, then divide cubic feet by 0.6 for 80 lb bags.
This concrete stair calculator finds exactly how much concrete you need to pour steps — in cubic yards, cubic feet, and 60/80 lb bags — with an estimated cost and a waste factor.
Poured concrete steps form a solid staircase wedge. Viewed from the side, the concrete fills a series of stacked rectangles — the bottom step carries the tallest column of concrete, the top step the shortest. That side-profile area is:
This calculator assumes solid poured steps. If you are building over a fill core (rubble or foam) to save concrete, subtract that core volume from the total.
Need slab or footing concrete too? Use our concrete calculator and concrete cost calculator.
Concrete stairs form a solid staircase wedge. The cross-section area equals the number of steps times (number of steps plus one), divided by two, times the riser height times the tread run. Multiply that area by the stair width, then convert to cubic yards by dividing by 46,656 cubic inches per yard.
For three 36 inch wide steps at a 7 inch riser and 11 inch run, you need about 0.36 cubic yards (roughly 9.6 cubic feet), or about 17 bags of 80 lb or 22 bags of 60 lb mix. Enter your exact dimensions above for a precise number.
An 80 lb bag yields about 0.6 cubic feet and a 60 lb bag about 0.45 cubic feet. Divide your total cubic feet (with waste) by those figures to get the bag count. For anything over about a cubic yard, ready-mix is usually cheaper than bags.
Small stoops of 3 to 4 steps are fine with bagged concrete. Once you pass roughly 1 cubic yard (about 45 bags of 80 lb), a ready-mix delivery is cheaper and far less work.
Yes. Poured concrete steps should be reinforced with #4 rebar and wire mesh, tied into the footing, to prevent cracking and settling. Steps also need a compacted gravel base and a footing below the frost line.
Concrete steps typically use a 6 to 7 inch riser and an 11 to 12 inch tread. The IRC caps residential risers at 7.75 inches and requires at least a 10 inch tread.