Perfect stairs alignment start with perfect measurement. Step by step method to setting out the diagonal for your stairs. Here’s a step-by-step method: 1. Understand the Basics of Stair Geometry Rise: The vertical distance from one tread to the next. Run: The horizontal distance of each step. Diagonal (Hypotenuse): The length along the stair's slope. Make sure you know the total rise (floor-to-floor height) and total run (the horizontal distance the stairs will cover). 2. Calculate the Number of