Average Step Height Of Interior Stairs

Step height is actually quite generic. If you have a two-story home then there’s a good chance you have a set of interior stairs. One question we get a lot is, “what is the appropriate step height for interior stairs?” Thankfully, the answer is quite simple.

One of the best ways to determine a good step height is to find the average step height. Because whatever is the average is what has been tried over and over again until a general size is decided on. This is what the average step height is. 

Why Does Step Height Matter?

Why Does Step Height Matter

Step height matters for a few different reasons. While certain heights look better than others, that’s the least of our concerns. There are other things like saving money with efficiency and most importantly, safety, that we need to consider.

As far as saving money goes, certain heights can use the least amount of materials. The same goes for certain depths. But what’s even more important than that is safety. We need to find out what is the safest height for the most people. 

Average Step Height, Width, And Depth

Average Step Height, Width, And Depth

Now it’s time to get down to it. The average step height in America is 7.5 inches. The depth is generally around 9 inches. As far as width goes, or the long part of the stairs, it’s primarily up to the homeowner.

But when it comes to the height and the depth, it’s important to follow the guidelines to prevent accidents. The mortality rate caused by falling down the stairs is frighteningly high, but much of it can be prevented by safer dimensions. 

Average Stairway Height (If Using The Average Step Height)

Now you are probably wondering how much room your stairs will take up or how tall stairs usually are. Well, the second is a given. Your stairs will be as tall as your first story as they will span from floor to floor.

The average ceiling height is nine feet on the first level, though it can be anywhere from seven feet to over twenty feet. But your stairway will be as tall as your first floor. And the span horizontally depends on the size of the steps. 

Terms And Parts Of A Stairway

Terms And Parts Of A Stairway

Each set of stairs has multiple parts that can help calculate their size and let you differentiate each section of the stairs. These parts and terms are used by architects and contractors for many different reasons. 


There are two different “runs” in stairways. There is the run of the step, which is the length of the step from the end to end the way that you step on the stairstep. This is the “width” of the step itself, the depth, not the length.

Then the other type of run is the total run. Which is the length of the entire set of stairs from the wall to the beginning of the stairs. This is the length you will travel to get from the bottom to the top of the stairs. 


The rise is very similar to the run only vertical instead of horizontal. The rise of the step is the height of the step. This is another term used for step height by architects and contractors so if you hear it, that’s what it is.

Then there is the total rise which usually equates to the ceiling height because this is the height of the stairs from the top to bottom. Although the rise can be taller than the actual stairs because that is another term. 


The stringer is another term similar to height. Stringer refers to the stair dimensions rather than the space of the dimensions of the stairs. The stringer height is the height of the stair structure. Not the space it takes up. 

Then the stringer length is the length of the stairs at an angle. The length of the stairs from top to bottom. This is angled with the angle of the board used to support the steps which should be straight. 


Speaking of angles, the angle is the angle of the stairs themselves. Not relative to the steps but to that stringer length and the floor. It’s easy to calculate the angle if you can use a square because it’s that simple.

The is only a bottom angle, not a top angle because you’d have to accommodate each step on top while on the bottom you have a straight line to work with no matter where you measure the angle. That’s why it’s so easy. 


The tread is the actual material used to cover the step. This is usually a board that creates the steps that we step on when going up the stairs. But it can be made of any strong, solid material. Tread only refers to the steps. 


Headroom is an obvious term used to describe the shortest distance from the steps to the ceiling. That area where you will have the least amount of room. It is before the floor opens but right as you are passing the bottom ceiling. 

It’s important that there’s enough headroom for anyone to pass under without any problems. The lower the ceiling is cutoff, the more headroom there will be. So cutting it off at the first step is the safest bet. 


The mount is where the stairwell ends. Sometimes, a mount will end just below the ceiling, creating an additional step using the ceiling. This is a standard mount. But there is also one other type of mount.

The other type of mount is called a flush mount. A flush mount puts the top of the stairs flush with the ceiling or upper-level floor. This is harder to install but it can be more comfortable as you have more room on the last step. 

How To Calculate Stair Size Using The Average Step Height

How To Calculate Stair Size

Calculating the size of your stairs and what size each step needs to be isn’t something that you will passively know. Correct calculations and formulas are necessary unless you’re into dangerous estimations. 

The easiest way to calculate the stair size is to use a stair calculator. This tool will let you know everything you need to know and teach you the complex formulas used in calculating the size of your stairs. 

Cost To Add Stairs With Average Step Height

You may be redoing old stairs or building a new house. But chances are, you are here because you are putting in new stairs. The cost of adding stairs really depends on where you are adding the stairs.

The average cost of adding stairs is just under $2000. But this is just an average. Some people only pay a couple of hundred while others will pay $10,000 for the nicest staircases that money can buy.

Related: How to Remove and Install Carpet on the Stairs

But there are a lot of things to take into consideration. These things include the material used to build the stairs, if they are interior or exterior, and how tall the stairs need to be. A full staircase isn’t the same as steps to your front porch.

Wood Stairs

The easiest way to calculate stair cost is by step. Most wood stairs cost about $100 to $200 per step. This is if you hire someone to do it as if you do it yourself you only pay for materials which is much cheaper. 

Concrete Steps

Concrete steps are uncommon indoors but quite common outside. They are usually about twice as much as wood stairs, ending up at around $300 per step. This is why they are not nearly as common as wood stairs. 

Iron Stairs

Iron stairs are quite expensive but are usually bought as one piece and not build by a professional on-site. You can expect to pay about five times as much for iron stairs as wood stairs. A great alternative is steel, which is half the price of iron. 

Glass Stairs

Glass stairs are very uncommon as steps and more common as railing or accents. That said, you can buy glass stairs for about ten times the cost of wood due to the dangers of installing it and the price of glass. 

Stone Stairs

Any type of stone staircase will cost anywhere from $100 to $1000 per step, depending on the stone you use. On average, they will cost significantly more than wood unless you salvage the stone yourself. 

Brick Stairs

Brick stairs are cheaper than stone stairs on average but can cost about twice as much as wood stairs. Though if bought in bulk you can get brick stairs at quite a deal, so be on the lookout, especially if you want standard colors. 

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Should My Step Height Be Average?

The reason it’s important to know the average step height is because it’s one of the safest step heights. But you can always change this depending on your space and your family. Kids may need shorter steps while tall people may want taller ones.

It all depends on your needs, but staying in a range is a good idea. For best results, hire a contractor to help you out and find out what is the best step height for your family and home. You may be surprised what you find out!