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Concrete Steps Calculator

How much concrete solid steps and a top platform need, in cubic feet, cubic yards or cubic metres, with waste and a bag count from the yield printed on your bag.

Your steps

Units
The platform at the top is the last step.
Landing at the top, e.g. in front of a door. 0 for none.
Waste and bags
Printed on the bag: cubic feet in Inches mode, litres in Metric mode.

Concrete 27.42 cu ft (1.015 cu yd), 30.16 cu ft (1.117 cu yd) with waste. Results and details

Worked example: edit any value

Concrete needed

Concrete volume 27.42 cu ft (1.015 cu yd)
With waste 30.16 cu ft (1.117 cu yd)
Bags enter a bag yield

Total rise 1 ft 9 in

Volume of solid steps only. Footings, a base layer, rebar and forms are separate; follow your local requirements for footing depth and reinforcement.

Concrete steps elevationSolid concrete steps: 3 risers of 7 in, goings of 11 in, top platform 36 in deep.1 ft 9 intotal depth 4 ft 10 in
Elevation, to scale. Dashed lines show the riser-high layers used in the calculation.
How this result was calculated
  1. Layer by layer1: 48 × 7 × 58; 2: 48 × 7 × 47; 3: 48 × 7 × 36Each riser-high layer runs from that riser face to the back of the platform.
  2. Total (closed form)W × h × R × ((R − 1) × g ÷ 2 + P) = 48 in × 7 in × 3 × ((3 − 1) × 11 ÷ 2 + 36) → 27.42 cu ft (1.015 cu yd)
  3. With waste27.42 cu ft (1.015 cu yd) × 1.1 = 30.16 cu ft (1.117 cu yd)
All values (table)
ItemValueNote
Risers3
Riser height7 in
Going11 in
Width48 in
Platform depth36 intop landing
Volume27.42 cu ft (1.015 cu yd)
With 10 % waste30.16 cu ft (1.117 cu yd)
Bagsn/aenter a yield

How the volume is worked out

Solid steps can be read as stacked slabs, one riser high each. The bottom slab runs from the face of the first riser all the way to the back of the platform; each slab above is one going shorter. Adding them gives a closed formula: width × riser × risers × ((risers − 1) × going ÷ 2 + platform depth). The calculator does both and the tests check they agree.

Count the platform at the top (for example in front of a door) as the last step. If the door threshold is the top, set the platform depth to the landing you want there.

Worked example

Three risers of 7 in, 11 in goings, 48 in wide, with a 36 in platform at the top:

  • Slabs: 48 × 7 × 58 + 48 × 7 × 47 + 48 × 7 × 36 = 47,376 cu in.
  • 27.42 cu ft = 1.02 cu yd; with 10 % waste 30.16 cu ft.
  • If your bag says it yields 0.6 cu ft, that is ⌈30.16 ÷ 0.6⌉ = 51 bags.

These are automated test fixtures (concrete K1 and the bag test). Always use the yield on the bag you buy.

Not included

Footings below the frost line, a gravel base, reinforcement, forms and any hollow (stepped-underside) design are not part of this volume. Outdoor steps attached to a house usually need footings and reinforcement set by your local code; ask before you pour.

Questions people ask

These are questions Google showed under "People also ask" for related searches (checked 2026-10-24), answered here with the same tested formulas the calculators use.

How do I calculate how many concrete steps I need?

Measure the height from the ground (or footing top) to the door threshold or landing, divide by your maximum riser and round up. For example, 21 in to a door at a 7 3/4 in maximum is ⌈2.71⌉ = 3 risers of 7 in, with the top platform as the last step. Then enter the risers here for the concrete volume.