Concrete Stairs Calculator
By Vinod Kondeti · Updated
Solid poured steps are a stack of blocks. The bottom step is one rise tall, the next is two rises, and so on. Total volume = width × run × rise × n(n+1)/2. The calculator applies this for any number of steps.
How do I measure for a stairs pour?
- Rise is the height of one step and run is the depth of one tread, both in inches.
- Treat a top landing deeper than one tread as a separate slab at the full stair height.
- The formula assumes solid fill. If you fill the inside with compacted rubble, your actual volume will be smaller.
Stairs concrete questions
How much concrete for 3 steps, 4 ft wide, 7 in rise, 11 in run?
4 × (11÷12) × (7÷12) × 6 = 12.8 ft³ = 0.48 yd³, about 22 bags of 80 lb mix.
Why does each extra step add more than the last?
Each new step sits on top of the ones below, so the bottom tread runs the full height. Adding a fourth step to the example adds about 67% more concrete.
Bag yields: 0.30 / 0.45 / 0.60 ft³ for 40 / 60 / 80 lb standard concrete mix (manufacturer data sheets). The concrete guide has the formulas and worked examples.
Sources
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