How it works
The calculator stacks the steps as slabs that all reach the ground: the bottom one is one rise tall, the next two rises, and so on. The treads below the top are one run deep; the top one is the landing depth, or one run when there is no landing.
Volume = Width × Rise × (Run × n × (n − 1) ÷ 2 + n × Top depth)
Without a landing: Volume = Width × Rise × Run × n × (n + 1) ÷ 2
Concrete to order = Volume × (1 + Extra ÷ 100)
Bags = ⌈ Concrete to order ÷ Yield per bag ⌉
n is the number of steps; ⌈ ⌉ means rounding up to the next whole bag. The volume itself is not rounded.
Units are converted internally, so you can enter the rise in inches and the width in feet; the result is shown in cubic yards and cubic feet (or cubic meters and liters). The default yield of 0.60 cu ft is QUIKRETE’s figure for an 80 lb bag of its Concrete Mix – change it to match your bag. This tool estimates material quantity only; step sizes, footings and reinforcement come from your plans and local code.
Worked example
Inputs
- Number of steps
- 3
- Rise per step
- 7 in
- Run per step (tread depth)
- 11 in
- Step width
- 4 ft
- Yield per bag
- 0.6 cu ft
- Extra concrete
- 0 %
Result
- Concrete to order
- 0.475 cu yd (12.83 cu ft)
- Bags
- 22
- Total height
- 21 in (1.75 ft)
- Total depth
- 2.75 ft (33 in)
Common mistakes
- Counting treads instead of risers. Three steps up to a porch have three risers; if you enter one step too few the bottom step is left out of the volume.
- Treating steps as one big box (total height × total depth × width). For three steps that overstates the concrete by half, and by more for longer flights, because the space under each tread above the bottom one is not concrete.
- Entering the rise in feet or the width in inches. Check the unit next to each field – a 7 ft rise is twelve times a 7 in rise.
- Forgetting a footing or a thickened edge below the bottom step. Calculate it separately, for example with the concrete footing calculator, and add it.
- Taking step sizes, footings or reinforcement from a calculator. Those come from your plans, local code or a qualified professional.
Assumptions and limits
- Steps are solid concrete down to the ground, poured as one block. Hollow steps or steps over a gravel or rubble fill use less concrete.
- Every step has the same rise and the same tread depth; only the top tread may be deeper (the landing).
- The steps are straight and rectangular – no flared sides, curved fronts or nosings. Side walls (cheek walls) beyond the step width are not included.
- Bags are rounded up to whole bags after the extra allowance. Without a yield, only the volume is shown.
- This is a material quantity only, not a structural design.
Frequently asked questions
How do I calculate the concrete for steps?
Treat each step as a slab that reaches down to the ground. With 3 steps, 7 in rise, 11 in run and 4 ft wide, the bottom step is 7 in tall, the next 14 in and the top 21 in, all 11 in deep – that adds up to 4 × 7/12 × 11/12 × 6 ≈ 12.8 cu ft, or about 0.48 cu yd.
How many bags of concrete do I need for 3 steps?
Divide the volume by the yield printed on the bag and round up. QUIKRETE’s data sheet lists about 0.60 cu ft for an 80 lb bag of its Concrete Mix, so the 12.8 cu ft above needs 22 bags before any extra.
How is a landing handled?
The landing is the top step made deeper. Enter its front-to-back depth; the calculator uses it for the top level instead of the tread depth, so the steps below stay unchanged.
What rise and run should my steps have?
Step dimensions are set by your local building code and your plans. This calculator doesn’t recommend them – ask your building department or a qualified professional.
Can I reduce the concrete with fill?
Many builders fill the inside of large steps with compacted gravel or rubble. The calculator assumes solid concrete, so subtract the fill volume yourself if your plans call for it.
Sources
- QUIKRETE Concrete Mix (No. 1101) Product Data Sheet — The QUIKRETE Companies. Yield per bag: 40 lb ≈ 0.30 ft³, 50 lb ≈ 0.375 ft³, 60 lb ≈ 0.45 ft³, 80 lb ≈ 0.60 ft³, 90 lb ≈ 0.675 ft³.
- NIST Handbook 44, Appendix C – General Tables of Units of Measurement — National Institute of Standards and Technology. Exact unit definitions: 1 in = 2.54 cm, 1 yd³ = 27 ft³, 1 US gal = 231 in³, 1 lb = 0.45359237 kg.
Method reviewed November 4, 2026