# 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?

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The general rule (in the US) is 7-11 (a 7 inch rise and 11 inch run). More exactly, no more than 7 3/4 inches for the riser (vertical) and a minimum of 10 inches 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 + 1 tread width equals between 24 and 25 in inches.

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

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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 '14 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")
• minimum tread depth (10")
• maximum rise (7.75")
• maximum tread depth variability (3/8")
• maximum rise variability (3/8")
• maximum slope of riser (30°)
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Some building codes are more strict on variability than this. But in general it is a good guideline. +1 – RyanWinchester Aug 13 '14 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.

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According to Sheldon Cooper, it's 2mm :) – Doresoom Jul 22 '10 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.

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Within reason, of course. You wouldn't want stairs that are 2 feet tall. :) – aphoria Jul 23 '10 at 0:51
I've actually taken to taking two steps at a time so 2 feet may not be that bad for me ;) – Wayne Werner Jul 23 '10 at 4:06
@Wayne.. wouldn't that be a little close to three stairs at a time? :) – warren Jul 28 '10 at 19:54

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").

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## protected by Community♦Aug 13 '14 at 13:49

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