Standard Stair Dimensions: Designing a Perfect Set of Stairs

standard stair dimensions

What are Standard Stair Dimensions?standard stair dimensions

The general rule for standard stair dimensions that is accepted by many general contractors and stair designers across the United States is known as the “7-11” rule. This means the rise is 7 inches and the run is 11 inches. This rule can be applied to any staircase design, but before we can start applying this rule to our stair design, let’s get to know some of the terms used out in the field. We’ll also take a look at some other standard stair dimensions offered by the Stairbuilders and Manufacturers Association.

Terminology and Measurements Used for Standard Stair Dimensions

  • Staircase Riser – the staircase riser is the vertical distance from the top of one tread to the top of the next tread. The maximum riser height is 7 ¾ inches with 7 inches being the general measurement. Staying inside the riser range of 7 – 7 ¾ inches prevents the stairs from being too steep or too low when walking up or descending the staircase.
  • Staircase Tread – the staircase tread, also known as the run, is the horizontal distance from the face of one riser to the face of the next riser. It’s more easily described as the distance from the front edge of the stair to the back of the step. Standard stair dimensions call for an 11 inch tread with the minimum measurement being 10 inches. A good staircase tread allows the majority of your foot to have enough room to rest on the stair.
  • Staircase Headroom – the staircase headroom is the vertical distance between the top of the stair tread and the bottom of the overhead ceiling. The minimum distance allowed is 6 feet, 8 inches. Making sure there is plenty of room overhead allows people to safely use the staircase without needing to duck or take their eyes off the stair path to check for other obstacles.
  • Staircase Width – the staircase width is determined by how long the staircase tread is. The minimum width allowed is 36 inches, not including the handrails. Making sure the staircase is wide enough allows users to safely carry large items up and down the stairs. It also allows multiple people to use the staircase in both directions in case of an emergency.standard stair dimensions

A Simple Formula to Calculate The Right Dimensions

When the general “7-11” rule doesn’t apply to your staircase design, a simple formula can be used to calculate the correct dimensions. The formula says that 2 risers and 1 tread must equal a minimum of 24 inches and a maximum of 25 inches when added together. For example, two risers, each measuring 7¼ inches, equals 14½ inches. That means the tread needs to be between 9½ – 10½ inches to fall between the required 24 – 25 inches. Following this simple formula when standard stair dimensions don’t apply, will help you achieve the perfect staircase that meets all the necessary requirements.

Additional Staircase Measurements

According to the Stairbuilders and Manufacturers Association, there are a few other measurements and dimensions that need to be taken into consideration when designing your staircase. Treads and risers have a maximum variability of 3/8 inches. Stairs that are outside these requirements become unsafe to users and present situations with increased chances of trips and falls. Also, the slope of the riser cannot be greater than 30°. This also leads to unsafe stairs.

When it comes to designing the perfect set of stairs, take standard stair dimensions into consideration. When those dimensions don’t apply to your design, use the simple stair formula to calculate the right dimensions that fit your project. For more information regarding Stair Specifications, click here or click the button below to download our FREE Stair Manual and Order Form.

 

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