How are stair dimensions calculated?

Total rise divided by a comfortable riser height to determine step count and dimensions.

What makes stairs comfortable versus awkward?

Consistent riser height and tread depth within ergonomic guidelines.

Why must all risers be equal height?

Uneven risers create a significant trip hazard since people expect consistent step height.

Stair Calculator - CalculatorLabs.net

Stair Calculator

Calculate the number of steps, riser height, and total run for a staircase based on total rise.

Total Rise (in)

Target Riser Height (in)

Tread Depth (in)

Number of Risers-

Actual Riser Height-

Number of Treads-

Total Run-

About the Stair Calculator

The Stair Calculator works out a safe, comfortable set of stair dimensions from the total vertical rise you need to climb.

It splits the total rise into evenly sized risers close to your target height, then calculates how many treads and how much horizontal run the staircase will need.

How to Use This Calculator

Enter the total rise — the full vertical height the stairs need to climb.
Enter your target riser height (7-7.75 in is common for comfort and code).
Enter the tread depth you plan to use.
Click Calculate.

Formula

Number of Risers = Round(Total Rise ÷ Target Riser Height). Actual Riser Height = Total Rise ÷ Number of Risers. Number of Treads = Risers − 1. Total Run = Treads × Tread Depth.

Example

A staircase with 108 in of total rise and a 7.5 in target riser height needs 14 risers of exactly 7.71 in each, 13 treads, and a total run of 130 in at a 10 in tread depth.