Determine Number of Treads

What happens in this clip

A critical rule in stair layout is that the number of treads is always one less than the number of risers. This is because the deck itself serves as the final top step, eliminating the need for an additional tread at the very top. So, if you have 8 risers, you will need 7 treads.

Goal: Apply the 'number of risers minus one' rule to find the correct number of treads needed for your stair stringers.

About the full video

This video provides step-by-step instructions for accurately laying out deck stair stringers by calculating the total rise, determining the number of risers and treads, and then calculating the total run to find the precise landing point for the stairs. This method helps avoid common mistakes in stair construction.

Step 4 of 6: Determine Number of Treads (Steps)

For any staircase, the number of horizontal treads (the surfaces you step on) will always be one less than the number of vertical risers. If you determined you need 13 risers, you will need 12 treads.

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