Concrete Stairs Calculator
Solid poured steps: set the count, rise, run, and width — get yards and bags. Defaults are code-standard exterior stairs.
How the volume is figured
Solid stairs are a stack of blocks: step 1 is one riser tall, step 2 is two risers tall, and so on. Total volume = width × tread × rise × n(n+1)/2 for n steps. Pouring against a wall or filling over rubble/CMU cores reduces the volume — this calculator assumes fully solid, which is the safe over-estimate.
Forms first, concrete second: stake and brace every riser board. A blown form mid-pour is the worst afternoon in DIY concrete.
Common questions
How much concrete do I need for steps?
For solid poured stairs, each step is a block: width × tread depth × (step number × riser height), summed over all steps. Four 4-ft wide steps at a 7" rise and 11" tread come to about 0.79 cubic yards — the calculator handles any configuration.
What is the standard rise and run for concrete steps?
Code-friendly outdoor steps: 7 to 7.5 inch rise, 11 inch minimum tread, every riser within 3/8" of the others. The comfortable-stride rule: 2 × rise + run ≈ 25–26 inches.
Can I pour stairs with bagged concrete?
Yes — most exterior stoops are 0.5–1.5 yards, squarely in bag territory. Use a 4,000 PSI mix, pour bottom step up in one session, and don't skip the form bracing: wet concrete pushes hard on riser boards.
Do concrete steps need rebar?
Steps attached to a structure or taller than 3 risers should get a #3/#4 grid and, critically, rest on footings below frost depth — steps poured on grade alone will settle and tip away from the house.