LayoutWise

Concrete Steps Calculator

Enter the steps and the landing at the top. You get the concrete in yards and bags, plus the forms you'll need to pour them.

Your steps

1. Steps
Width
ft
in
Landing depth at the top (0 for none)
ft
in

Concrete

1.38 yd³

37.2 cu ft with 10%

80 lb bags

63

0.6 cu ft each

Height

1' 9"

3 x 7"

Depth

5' 9"

front to back

Side view

Bags or ready-mix

Solid steps on grade, each step resting on the ground. Filling the core with compacted gravel or broken concrete can cut the concrete by a third on tall steps.

Shopping list

  • ✓Concrete: 1.38 cu yd — 63 x 80 lb bags, or order 1.5 yd ready-mix
  • ✓Side forms: 1 sheet of 3/4" plywood (both sides)
  • ✓Riser forms: 3 x 2x8 at 4' 6", beveled at the bottom so you can finish the tread
  • ✓Stakes, 2x4 bracing, form-release oil, and an edger and broom for the treads

Steps against a house usually sit on a footing below the frost line — check with your building department.

How much concrete for steps?

Solid steps on the ground are a stack of blocks: the first step is one rise tall, the second two rises, and so on, each one tread deep. Add the landing at the top, which is the full height of the steps. Multiply each block's width x depth x height and add them up.

Example: three 7" steps with 11" treads, 4 feet wide, and a 3-foot landing. The steps hold 12.8 cu ft and the landing 21 cu ft — about 33.8 cu ft, or 1.38 cubic yards with 10% extra. That's 63 bags of 80 lb concrete, so ready-mix is worth pricing.

Step dimensions

Outdoor steps follow the same residential code as indoor ones: risers no taller than 7 3/4" and treads at least 10" deep. Keep every riser the same height. A landing outside a door should be at least 36" deep.

Forms

Cut both side forms from 3/4" plywood in the shape of the steps, then set a riser board for each step, beveled along the bottom edge so you can trowel the full tread. Brace everything well — wet concrete pushes hard on the forms.

Planning indoor or deck stairs? Try the stair calculator. Pouring a slab too? Use the concrete calculator.