How it’s calculated
- Step blocks = width × rise × run × n(n + 1) ÷ 2
- Landing = width × landing depth × (n × rise)
- Volume = steps + landing
Worked example
3 steps, 7 in rise, 11 in tread, 4 ft wide, no landing.
Inputs
- Number of steps
- 3
- Rise per step
- 7 in
- Tread depth (run)
- 11 in
- Stair width
- 4 ft
- Top landing depth (0 if none)
- 0 in
- Extra for waste
- 0 %
- Bag size
- 80 lb bag
Results
- Concrete to order (with waste)
- 0.48 cu yd
- Net volume
- 0.48 cu yd
- Or bags
- 22 bags
Assumptions and limits
- Steps are solid concrete down to grade (no fill or hollow core).
- All steps have equal rise and run.
- Bag counts use typical manufacturer yields for pre-mixed concrete. Check the yield printed on your bag.
Verify the result against the applicable local code, adopted code edition, manufacturer instructions and project requirements. See our methodology.
Questions
What rise and run should concrete steps have?
The IRC limits residential risers to 7¾ in and requires treads of at least 10 in. Local amendments may differ, so confirm with your building department.
Can I reduce concrete with fill?
Yes. Many builders place compacted gravel or rubble inside the form. Subtract the fill volume from this result.