Calculate Number of Risers

What happens in this clip

To calculate the number of risers, divide your 'total rise' measurement by a comfortable and code-compliant 'unit rise' (the height of a single step). Standard building codes often suggest a maximum unit rise of about 7.75 inches, but a comfortable height is usually around 7.5 inches. In the video's example, with a total rise of 60 inches, dividing by 7.5 inches (60 / 7.5) yields 8 risers.

Goal: Determine the number of individual risers needed for the stairs by dividing the total rise by an appropriate unit rise (individual step height).

What's used

Tools

• Calculator

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 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 (this video)
   • 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

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