Concrete Step Calculator
Calculate concrete needed for steps and stairs. Enter tread depth, rise height and width to get cubic yards and bags needed.
Stair Dimensions
Concrete Required
How to Calculate Concrete for Solid Steps
Calculating the volume of concrete for stairs is more complex than a standard flat slab because stairs are three-dimensional wedges. When you pour concrete steps directly on the ground (solid poured stairs), the bottom step requires the least concrete, and the top step requires the most because it goes all the way down to the base.
The calculator uses a specialized mathematical progression formula to calculate the exact volume of the solid triangular prism formed by the stairs. Ensure you measure the "Rise" (vertical height of each step) and the "Tread" (horizontal depth of each step) accurately.
Stair Calculation Formula
Total Volume = [Width × Tread × Rise × (N × (N + 1)) / 2]
Where N is the total number of steps. The result is calculated in cubic inches, then divided by 1,728 to find cubic feet, and divided by 27 to find cubic yards.
Frequently Asked Questions
How much concrete do I need for 3 steps?
For 3 solid poured steps that are 4 feet wide, with a standard 11-inch tread and 7-inch rise, you will need approximately 0.28 cubic yards of concrete, which equals about thirteen 80lb bags.
What is the standard size for concrete steps?
The standard building code rule for steps is a 7-inch rise and an 11-inch tread (often called the 7-11 rule). The width is typically a minimum of 36 inches (3 feet).
How do you calculate cubic yards for stairs?
Solid stairs form a triangular prism. You can calculate it using the formula: Width × Tread × Rise × (Number of Steps × (Number of Steps + 1)) / 2. Divide the result in cubic inches by 46,656 to get cubic yards.
How many bags of concrete for steps?
Once you know the cubic yardage of your stairs, multiply by 45 to find how many 80lb bags you need, or multiply by 60 for 60lb bags. Always add a 10% waste margin.