Calculate Rise and Run

What happens in this clip

Using the total rise measurement (109 inches), calculate the individual rise and run for each step. Start by dividing the total rise by a standard comfortable riser height (e.g., 7 inches). This gives an approximate number of risers (109 / 7 = 15.5). Since you can't have half a riser, round to the nearest whole number (15 risers). Divide the total rise by the number of risers to get the exact individual riser height (109 / 15 = 7.26 inches, or approximately 7 1/4 inches). Then, determine the run (tread depth). A common rule for comfortable stairs is that the rise plus the run should total between 17 and 18 inches. With a 7 1/4 inch rise, a 10-inch run gives 17 1/4 inches, which is within the comfortable range.

Goal: Determine the precise dimensions for each individual step (rise and run)

About the full video

This project provides a step-by-step guide on how to build a flight of straight stairs, including measuring the total rise, calculating individual step dimensions, laying out and cutting stringers, installing structural supports, and finally installing the risers and treads.

Step 6 of 6: Calculate Actual Tread Run

Using the total run and the number of treads, divide the total run by the number of treads to calculate the precise depth of each individual tread. For the example of a 120-inch total run and 12 treads, the actual tread run would be 120 inches / 12 treads = 10 inches per tread.

Open this step in the guide

Every video in How to Measure Stair Rise and Run

1. Step 1: Determine Total Rise

   • 0:04–0:30 Measure Total Rise
   • 2:54–4:34 Determine the Total Rise
   • 0:54–1:25 Calculate Final Total Rise

2. Step 2: Calculate Ideal Riser Height

   • 0:29–1:07 Calculate Rise and Run
   • 4:32–5:10 Calculate Individual Riser Height
   • 0:28–1:03 Calculate Approximate Number of Risers

3. Step 3: Determine Actual Riser Height

   • 4:32–5:10 Calculate Individual Riser Height
   • 1:03–1:44 Calculate Riser Height (Option 1)
   • 0:28–1:03 Calculate Approximate Number of Risers

4. Step 4: Determine Number of Treads (Steps)

   • 0:54–1:13 Determine Number of Treads
   • 3:54–5:04 Calculate the Number of Treads and Understand the Logic
   • 8:59–9:54 Calculate Number of Risers and Treads

5. Step 5: Measure Total Run

   • 1:31–2:57 Calculate Unit Run and Total Run
   • 1:13–1:29 Calculate Total Run
   • 9:54–10:28 Determine Tread Run and Total Run

6. Step 6: Calculate Actual Tread Run

   • 0:29–1:07 Calculate Rise and Run (this video)
   • 1:31–2:57 Calculate Unit Run and Total Run
   • 10:55–11:31 Calculate Overall Run (Treads)