How to Calculate Where Bottom of Your Stairs Will Land in Less Than Two Minutes

Moments in this video

1. 0:17–0:31 Measure Total Rise From How to Calculate How Many Stairs You Need, Step 1: Measure the Total Rise

   Measure the vertical distance from the top surface of your finished deck floor straight down to the level where the stairs will terminate. This measurement is known as the 'total rise'. For the example in the video, the total rise is 60 inches.

2. 0:32–0:54 Calculate Number of Risers From How to Calculate How Many Stairs You Need, Step 3: Calculate the Number of Risers

   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.

3. 0:54–1:13 Determine Number of Treads From How to Measure Stair Rise and Run, Step 4: Determine Number of Treads (Steps)

   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.

4. 0:54–1:13 Determine Number of Treads From How to Calculate How Many Stairs You Need, Step 5: Calculate the Number of Treads

   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.

5. 1:13–1:29 Calculate Total Run From How to Measure Stair Rise and Run, Step 5: Measure Total Run

   With the number of treads determined, calculate the 'total run' of your stairs. A standard tread depth is often around 10 inches. Multiply your number of treads (7 in the example) by your chosen tread depth (10 inches). This calculation (7 treads * 10 inches/tread) gives a total run of 70 inches. This figure tells you how far horizontally the stairs will extend from the deck.

6. 1:13–1:29 Calculate Total Run From How to Calculate How Many Stairs You Need, Step 6: Determine the Total Run

   With the number of treads determined, calculate the 'total run' of your stairs. A standard tread depth is often around 10 inches. Multiply your number of treads (7 in the example) by your chosen tread depth (10 inches). This calculation (7 treads * 10 inches/tread) gives a total run of 70 inches. This figure tells you how far horizontally the stairs will extend from the deck.

Guides that use this video

• How to Calculate How Many Stairs You Need
• How to Measure Stair Rise and Run