Calculate Total Run

What happens in this clip

To find the total horizontal length (total run) of the staircase, multiply the individual tread depth by the number of treads. For example, if you have 13 treads, each 10 inches deep, the total run would be 13 * 10 inches = 130 inches (10 feet 10 inches). This measurement is crucial for laying out the full length of the staircase on the floor.

Goal: Determine the horizontal length of the staircase

What's used

Tools

• Calculator Windows Standard Calculator (shown)
• Smartphone calculator app

About the full video

This guide demonstrates essential techniques for accurately verifying stair stringer layout markings on a floor using a level and framing square before any cuts are made. It covers how to mark tread depths, align stringers to these marks, account for riser thickness and nosing, and calculate the number of risers and treads based on total rise and run to ensure precision and prevent costly errors in stair construction.

Step 6 of 7: Determine the Total Run

Multiply the number of treads (from Step 5) by the desired tread depth. A common tread depth is 10 to 11 inches, but this can vary. Ensure the tread depth is consistent and meets local code requirements. For example, if you have 13 treads and a desired tread depth of 10 inches, the total run is 13 * 10 = 130 inches.

Open this step in the guide

Every video in How to Calculate How Many Stairs You Need

1. Step 1: Measure the Total Rise

   • 0:15–0:29 Measure Total Rise
   • 0:01–0:28 Measure Total Vertical Rise
   • 0:17–0:31 Measure Total Rise

2. Step 2: Determine the Ideal Riser Height

   • 1:03–1:44 Calculate Riser Height (Option 1)
   • 1:44–2:33 Calculate Riser Height (Option 2) and Verify Code Compliance
   • 4:32–5:10 Calculate Individual Riser Height

3. Step 3: Calculate the Number of Risers

   • 0:32–0:54 Calculate Number of Risers
   • 8:59–9:54 Calculate Number of Risers and Treads
   • 7:42–8:55 Calculate Number of Risers

4. Step 4: Recalculate Actual Riser Height

   • 1:03–1:44 Calculate Riser Height (Option 1)
   • 4:32–5:10 Calculate Individual Riser Height
   • 1:44–2:33 Calculate Riser Height (Option 2) and Verify Code Compliance

5. Step 5: Calculate the Number of Treads

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

6. Step 6: Determine the Total Run

   • 1:13–1:29 Calculate Total Run
   • 1:31–2:57 Calculate Unit Run and Total Run
   • 6:51–8:30 Calculate Total Run (this video)

7. Step 7: Calculate Tread Depth

   • 2:05–2:24 Calculate Individual Riser Height & Tread Depth
   • 9:54–10:28 Determine Tread Run and Total Run
   • 8:50–10:30 Calculate Risers, Treads, and Total Run