Calculate Risers, Treads, and Total Run
From How to Calculate How Many Stairs You Need · Step 7 of 7 · Video by HouseImprovements
Showing 8:50–10:30 of the source video. Watch the full video with every moment.
What happens in this clip
Using the calculated total rise of 104 inches, the presenter divides this by an estimated number of risers (e.g., 14) to get an individual riser height of 7.43 inches (or 7 7/16 inches). This height falls within the acceptable code range. With 14 risers, there will be 13 treads (always one less tread than risers). The pre-manufactured stair treads are 11.5 inches wide, and with a 1-inch nosing, the effective tread depth (run per step) is 10.5 inches. Multiplying the effective tread depth (10.5 inches) by the number of treads (13) gives a 'total run' of 136.5 inches. This total run is the horizontal distance the staircase will cover.
Goal: This step demonstrates how to calculate the number of risers and treads, along with the total run, using the previously determined total rise and accounting for standard tread material dimensions.
What's used
Tools
- Calculator
- Paper and Pen
About the full video
This video provides a detailed guide on understanding and applying building codes for staircase construction. It covers essential terminology like stringer, riser, and tread, explains minimum requirements for headroom, riser height, nosing, and tread depth, and demonstrates how to measure total rise and calculate the number and dimensions of risers and treads to meet code and ensure a comfortable staircase.
What's said in this clip
risers and uh we can figure out where our last tread ends up underneath our bulkhead down there and make sure our head room is going to be all right okay so I've already worked out the math so we had our total rise of 104 in so 104 divided by 14 I just took a rough guess I originally divided it by 133 but that gave me too big of a rise so then I went up one more Riser so 14 was my guess 104 divided by 14 risers gives me 7.43 in which is 7 and 7 16 well that falls in our in our comfort zone for what our Riser Heights can be and it's it's pretty comfortable step honestly so we're going to use 7 and 716 and 14 risers now I already said we're we always end up with one less tread than we do Riser so that means we're going to have 13 Treads the tread material I have is 11 and 1 12 in wide and I'll show you that in a few minutes it's a pre-manufactured tread um so when I deduct my nosing off there which is an inch I'll have 10 and 1 half inch Treads or my run will be that okay so if I have a 10 and 1/2 inch run on every tread which was 13 Treads that's 1362 is my total Run Okay so that's my my distance from so my that means my stair set of stairs is
Automatically transcribed from the source video.
Step 7 of 7: Calculate Tread Depth
Divide the total run (calculated in Step 6) by the number of treads (from Step 5). This gives you the actual tread depth. For example, if you calculated a total run of 130 inches for 13 treads, the actual tread depth is 130 / 13 = 10 inches.
Every video in How to Calculate How Many Stairs You Need
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
Step 2: Determine the Ideal Riser Height
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
Step 4: Recalculate Actual Riser Height
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
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
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 (this video)
How to Calculate How Many Stairs You Need
This project outlines the process for calculating the number of stairs needed for a given rise, ensuring safety and code compliance.
Read the full guide Browse all guides
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