How Many Deck Stairs Do I Need

How Many Deck Stairs Do I Need?


Once you’ve built your dream deck, you may find that you want to connect it to the garden to enhance the overall indoor-outdoor flow of the space. It can be quite a daunting task to figure out how many deck stairs are required to comfortably get you from the deck to the ground below. Thankfully, there are a set of standard guidelines to assist you.

Naturally, the necessary number of deck stairs depends on the height of your deck from the ground. Local building guidelines will stipulate the maximum height of each step (riser height). With this figure in mind, you will be able to calculate how many deck stairs are needed for your specific project.

When it comes to deck stairs, building regulations have specific minimum requirements that will ensure any step is at a comfortable height for a person to use without risk of injury. There are also minimum requirements for tread depth (the depth of the step) and the total width of the stairs.

How Many Deck Stairs Do I Need

How Many Deck Stairs Do I Need?

It should go without saying that the number of deck stairs needed is dependent on the height of your deck from the ground. Every project is different, so there is no “one size fits all” approach to something like this. As a result, building regulations stipulate minimum requirements for the height and depth of deck stairs.

These minimum requirements are decided upon according to the human body’s ergonomics and its movement. The dimensions stipulated fall within a comfortable range for the average person to be able to move up and down a staircase with ease. The ideal riser height differs according to jurisdiction, but the general American average is around 7”.

Once you have the ideal riser height, you need to check the total height of your deck, as this will determine how many of the abovementioned 7” high stairs will be needed to get you from the deck to the ground level. Now that you have the total height of your deck from the ground, simply divide this figure by the ideal riser height, and you will have an estimated number of stairs for your deck.

Naturally, there will be differentiation according to the specific circumstances and project. The above simply describes the basic premise of determining the ideal number of stairs for your deck. This is the starting point from which we will explore the principles in further detail.

The number of stairs attached to your deck will affect several factors:

  • Firstly, the number of deck stairs will directly influence the project’s overall cost. More stairs equate to more materials such as deck boards and riser pieces. It will also naturally equate to more labor.
  • Secondly, the number of stairs will directly affect how far the stairs reach out from the deck. Suppose you have limited space, such as a property boundary or other feature. You will need to carefully consider how far your staircase will reach in that case. You will need to make the necessary adjustments to ensure that it is a good fit.
  • Thirdly, to determine the ideal dimensions for a set of deck stairs in your area, you must consult your local building codes. The codes will stipulate all the ranges within which your stair dimensions will need to fall. This dimension range will give you a good starting point from which to work, and it will also ensure that your staircase falls within the legal requirements for a set of stairs.

Because the building codes for stairs have been designed according to human economics, following these guidelines will ensure your staircase is comfortable and ensures no user becomes injured at any stage.

How Many Deck Stairs Do I Need

Stair Risers Number & Height

The stair riser refers to the height of the individual step. According to your local building codes, there are minimum and maximum requirements for this dimension. Your steps must fall within this range to ensure compliance, safety, and user comfort.

Regulations give riser heights that range from a minimum of 5” to a maximum of 8”. While the minimum height is not too much of a concern, the maximum height is something to pay attention to. These heights vary enormously according to jurisdiction, with some areas stipulating a maximum height of 7 7/8”.

The general recommended riser height across the country is between 6 ½” and 8”. On average, most consider a riser height of 7” to be ideal. your riser height must be consistent throughout the set of stairs. There should be no differentiation of more than 3/8” between stair heights.

Inconsistent stair heights can potentially cause injury to any user of the stairs.

Stair Tread Depth

The tread depth is another aspect to consider, and this will also help you determine the number of stairs needed. The minimum tread depth is calculated based on the size of an average foot and the length of a person’s stride. If the tread is too narrow, a staircase can be difficult to walk up/down and may cause injury.

Deeper stairs, however, are actually recommended as these can allow for slower, more comfortable ascent and descent. They can also be more aesthetically pleasing, provided you have sufficient space. Tread widths should sit somewhere between 9 ¼” and 14”. The ideal average tread width is 10 ¼”, allowing you to use two 2×6” timber pieces.

Total Stair Run & Rise

Your total stair run essentially refers to how far the staircase will project from your deck. The total rise refers to the height from the top of the deck to the ground below. Both dimensions will assist in your calculations of the number of stairs required. This is naturally completely project-dependent.

Stair Width

A staircase can essentially be built to any desired width. While a set of stairs should be no narrower than three feet, it can be as wide as you would like. A wide set of deck stairs, especially if the stairs have a higher tread depth, can create an extension of the living space and an enjoyable social space for the home users.

We have other information on the links below about deck stairs and materials to help you make your choice.


By following the guidelines above while consulting your local building regulations, you will be able to accurately calculate the ideal number of stairs for your specific deck project.

This will ensure that anybody using your deck will be able to move freely onto the ground below with ease and comfort. It will also ensure that your deck stairs are well integrated into their surrounds and your building project overall.


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