Calculators/ Concrete/Concrete Stairs Calculator
Concrete Stairs Calculator
Concrete volume for a flight of poured steps.
Concrete Stairs Calculator
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A flight of poured steps is a stack of rectangular blocks that each get longer as you go down. The volume grows much faster than the step count, so estimating by eye is almost always short.
How this is calculated
- Each step sits on all the steps below it, so step i contributes rise × run × width × i.
- Summing that over every step gives width × run × rise × n(n+1)÷2, where n is the number of steps.
- This assumes the flight is a solid pour against a cut slope. If the stairs sit on fill or a formed void, subtract that volume.
Frequently asked questions
What is a comfortable rise and run for stairs?
Seven inch rise with an eleven inch run is the standard comfortable combination and satisfies most residential codes. Rise should never exceed 7.75 inches in most US jurisdictions.
Do concrete stairs need rebar?
Yes. Poured steps carry concentrated loads at the nose of each tread and will crack without reinforcement. Most flights use #4 bar.
Should stairs be poured with the slab?
Pouring monolithically with the landing avoids a cold joint and is stronger, but needs more formwork and a larger single delivery.