Concrete Steps Calculator
Concrete volume and bag count for a solid cast staircase, treated as a stack of full-depth blocks.
Results
Worked example
Five steps at 180 mm risers and 280 mm treads, 1.2 m wide. The stacking factor is 1 + 2 + 3 + 4 + 5 = 15. Volume = 1.2 × 0.28 × 0.18 × 15 = 0.907 m³. Bags = 0.907 ÷ 0.0135 = 67.2, rounded up to 68 bags. Total rise is 0.90 m and total run is 1.40 m.
How it works
A solid staircase is a stack of boxes: the first step is one riser tall, the second is two, and so on. Volume = width × tread depth × riser height × n(n + 1) ÷ 2, where n is the step count. Bag counts use a yield of about 0.0135 m³ per 30 kg bag of pre-mix, the same assumption as our other concrete calculators.
FAQ
Does this include a landing or side walls?
No. It covers the steps only, on the assumption of a solid pour. Add landings, cheek walls, and any footing separately.
My steps will be formed hollow, not solid. Does that matter?
Yes. Hollow-formed steps over a sloped base use considerably less concrete. This calculator gives the solid-cast figure, which is the safe upper estimate for ordering.
Estimates only. Mississippi Maple provides approximate material estimates for planning. Riser and tread dimensions must comply with your local building code; verify quantities with your supplier or contractor before purchasing.