Calculate Number of Risers and Treads

What happens in this clip

With a total rise of 104 inches, the speaker estimates 14 risers. Dividing 104 by 14 yields approximately 7.43 inches per riser (or 7 7/16 inches), which falls within his local code's acceptable range (5 3/4 to 8 inches). For a staircase, the number of treads is always one less than the number of risers, meaning there will be 13 treads. He notes that if the initial estimation of risers results in an individual riser height outside the acceptable range, the number of risers should be adjusted (e.g., adding or removing one) and the calculation repeated.

Goal: Using the total rise, calculate the optimal number of risers and corresponding treads, ensuring individual riser heights are within code and comfortable limits.

What's used

Tools

• Calculator

About the full video

This video provides a detailed guide on planning and dimensioning a staircase, focusing on understanding building codes, measuring key components like total rise, total run, headroom, and selecting appropriate materials. It covers essential terminology, calculation methods, and practical considerations for ensuring a safe and compliant staircase installation.

Step 3 of 7: Calculate the Number of Risers

Divide the total rise (from Step 1) by your chosen ideal riser height (from Step 2). Round the result to the nearest whole number. This will be your number of risers. For instance, if your total rise is 100 inches and you aim for a 7-inch riser height, 100 / 7 = 14.28, which rounds to 14 risers.

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 (this video)
   • 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

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