# Is there a standard height and depth for stairs?

Is there a standard (or a standard range for) the height and depth of each step in a flight of stairs?

The general rule (in the US) is 7-11 (a 7 inch rise and 11 inch run) (17.78cm-27.94cm). More exactly, no more than 7 3/4 inches (19.7cm) for the riser (vertical) and a minimum of 10 inches (25.4cm) for the tread (horizontal or step). You can find some more information here as well on other stair-related dimensions.

To calculate if the steps will be within the Building Codes specs: 2 times the step riser height + one tread depth equals between 24 and 25 in inches (60.96cm and 63.5cm).

example: (2 x 7.5") + 10 = 25 (2 x 19.05cm + 10 = 48.1cm)

• This is true for a very specific sub-set: residential staircases. The reality is that there is no standard, though (as others note). It's the ratio that's dictated by code--not the specific rise/runs.
– DA01
Jul 6, 2014 at 4:25

The Stairway Manufacturing Code Association published the International Residential Code (PDF Link) in 2006 which tells you just about everything you could ever want to know about stairs, including:

• minimum headroom depth (6' 8")
• maximum rise (7.75")
• maximum tread depth variability (3/8")
• maximum rise variability (3/8")
• maximum slope of riser (30°)
• Some building codes are more strict on variability than this. But in general it is a good guideline. +1 Aug 13, 2014 at 16:03

Not what you asked, but for safety the most important thing, even more important IMO than getting the right rise and run, is that every step is consistent. Varying as little as 1/4 inch in rise will make even a ballerina fall on her face if she's running up the stairs.

• According to Sheldon Cooper, it's 2mm :) Jul 22, 2010 at 18:46

It not so much about the rise and run lengths specifically ,but about the ratio of the Rise to Run. You should strive to hit a 30-35% ration of rise/run. A 7-11 is the most common and gives you the correct ratio, but any combination of rise to run that hits this 30-35% ratio would be fine.

• Within reason, of course. You wouldn't want stairs that are 2 feet tall. :) Jul 23, 2010 at 0:51
• I've actually taken to taking two steps at a time so 2 feet may not be that bad for me ;) Jul 23, 2010 at 4:06
• @Wayne.. wouldn't that be a little close to three stairs at a time? :) Jul 28, 2010 at 19:54
• 7-11 seems to me like 64% ratio of rise/run... Jan 20, 2017 at 18:28
• @jkjenner I think he is referring to 11*(1-0.35) = 7.15, not technically "ratio of rise/run". Should be "rise is 35% less than run" May 11, 2020 at 13:29

As a general rule your stairs should be built with this in mind and you won't bust code no matter where you live. 2 risers plus 1 tread must equal a minimum of 24" and a maximum of 25" when added together. Example ( 2 risers of 7-1/4" = 14-1/2" then your tread could be 9-1/2" to 10-1/2").

• Where is this from? Jul 14, 2019 at 19:40