Home > Concrete Calculator > Stairs Concrete Calculator
Stairs Concrete Calculator
Concrete for solid steps and staircases. Enter steps, tread, riser and width: get cubic yards and bags instantly.
Estimates only. Bag yields per manufacturer specs (80 lb ≈ 0.60 ft³, 60 lb ≈ 0.45 ft³, 40 lb ≈ 0.30 ft³). Ready-mix trucks carry ≈ 10 yd³. Always round up and confirm with your supplier.
Five solid steps, 4 ft wide, with 11 in treads and 7 in risers need about 0.99 cubic yards (1.09 with 10 percent waste). The free stairs concrete calculator below handles any step count and size, so your staircase order is right first time.
How to use the stairs concrete calculator
- Count the number of steps.
- Enter the tread depth (the flat part) in inches.
- Enter the riser height in inches.
- Enter the stair width in feet and add 10 percent waste.
Formula
Volume (solid steps) = ½ × (steps × tread) × (steps × riser) × width ÷ 27, giving cubic yards. This models the steps as a solid wedge; hollow or framed steps need less concrete.
Practical tips
- Keep risers equal: uneven steps are a trip hazard and breach most building codes.
- A 7 in riser with an 11 in tread is the comfortable standard.
- Pour steps and landing together where possible for a monolithic pour.
- Use a stiff mix so the step faces hold their shape in the forms.
Frequently asked questions
What is a comfortable step size?
A 7 inch riser with an 11 inch tread suits most people. Keep every step identical.
How much concrete for 5 steps?
Five 4 ft wide solid steps with 11 in treads and 7 in risers need about 0.99 cubic yards, or 1.09 with 10 percent waste (50 bags of 80 lb).
Should steps have rebar?
Yes for structural stairs: rebar ties the steps to the landing and stops cracking.
See all 12 tools in the concrete calculator hub or check rebar needs.
Worked examples
Example 1: 5 solid steps, 11 in tread, 7 in riser, 4 ft wide. Volume = 1.19 cubic yards. With 10% waste: 1.31 cubic yards (59 x 80 lb bags).
Example 2: 8 solid steps, 12 in tread, 7 in riser, 5 ft wide. Volume = 3.89 cubic yards. With 10% waste: 4.28 cubic yards (193 x 80 lb bags).
Note: this calculator models solid steps.
Stairs reference table (solid steps)
Cubic yards before waste; 80 lb bags include 10% waste.
| Steps | Cubic yards | 80 lb bags |
|---|---|---|
| 4 steps, 11×7 in, 4 ft | 0.79 | 40 |
| 5 steps, 11×7 in, 4 ft | 1.19 | 59 |
| 6 steps, 11×7 in, 4 ft | 1.66 | 83 |
| 8 steps, 12×7 in, 5 ft | 3.89 | 193 |
More stairs questions
How many bags for 5 concrete steps?
Five solid steps at 11 in tread, 7 in riser, 4 ft wide need 59 x 80 lb bags with 10% waste.