Building or renovating your investment property can be a lot of fun in many ways, but that is not a word most people use when building stairs. Staircases are considered one of the most complicated and challenging parts of an interior build, but there is a way to make it easier.

A stair calculator takes the guesswork out of it and makes planning a stair build a much more simple task. Spend less time testing your math skills and more time managing your properties.

Here is everything you need to know about stair calculators, how they work, and how to use them for your next project.

What Is the Purpose of a Stair Calculator?

Building stairs is a very technical job- but the complexity starts long before the first piece of material is picked up. Even designing stairs for a proposed floor plan involves several calculations and variables.

Building codes, safety regulations, and aesthetic best practices all rely on you getting the stairs right, so you need to have the dimensions down long before a project starts.

The point of a stair calculator is to turn this from a refresher of middle school math into a quick and easy task. All you need are a couple of details and the calculator can figure out the rest for you.

How Do Stair Calculators Work?

There are a few variations of stair calculators out there, but they all do the same thing. Some ask for more details off the bat, and others use simple calculations with minimal information to establish the rest of the measurements.

In essence, stair calculators work by taking set dimensions for a project (for example, how high the staircase needs to be to connect the two floors) and using those dimensions to determine the rest.

It is a much quicker and easier way of designing stairs for a specific space and reduces the room for error significantly.

What Details Are Used in Stair Calculations?

The details you need to input in a stair calculator depend on what you know and what you need to find out. By that, we mean there is more than one way to use a stair calculator.

In most cases, you use the most basic information to work out the more complex details.

Usually, calculators ask for the following details first.

Total Rise

How high do your stairs need to be all together? This is a pretty easy one to work out, since they need to reach from one floor to the next. All you need to do the get this detail is measure from the ground straight up to the next floor.

Stair Rise

You should also determine how high each of the individual steps should be. There are limitations on how high a step can be (19.6 cm or 7.75 inches in most cases). If you know what the individual rise has to be, you can easily work out how many steps you need.

Stair Run

The run is how deep the tread is on each step- meaning the bit you stand on. Again, some rules apply.

Building codes stipulate that the minimum length or tread depth must be 25.4 cm or 10 inches.

What Do These Figures Determine?

Based on the details above, a stair calculator can quickly give you accurate measurements for the following elements.

  • Number of Steps

By taking the total height the stairs need to climb- and how high each step has to be- you can figure out the total number of steps you need in your staircase.

Some calculators also give you the option to use the number of steps you want to figure out how deep and high each one should be.

As long as you input either how many steps you want or what width and depth you need them to be, you can use a stair calculator to figure out the rest.

  • Bottom Step Rise

Another consideration you need to make is the rise of the bottom step. In an ideal world, your dimensions will be divided evenly into perfectly equal stairs, but that is not always possible.

When the division is not even, the standard practice is to reduce the rise or the bottom step. This is the safest and most aesthetically pleasing solution.

Say, for example, your total rise is three meters, the step rise is 19cm, and the step run is 26cm. With 16 stairs, the bottom first step height would be reduced to 15cm to accommodate the required. height.

A stair calculator will automatically determine what depth the bottom step height needs to be to keep the rest of the staircase calculation even.

  • Total Run

Multiplying the run of each step by the number of steps gives you the total run. This is an important measurement in a construction project, as it determines how far out the staircase will come into the space.

Depending on the size and shape of the space available, you may realize that your proposed step rise and run won't work. You can then reassess the dimensions before you start the work- saving time, money, and a lot of frustration.

If you have a limit to how far the stairs can extend, you can use this dimension and the total rise to work out the angle, step rise, number of steps, and step run.

  • Stringer Length, Height, and Angle

The stringer is what your steps are built on. It is constructed at the sides of the stairs to 'string' the steps together.

Stringers must be constructed correctly- and in the right position. Otherwise, the entire staircase will be out.

A stair stringer calculator determines three measurements:

Stringer height (the distance from the floor to the highest corner of the stringer)

Stringer length (measured from the longest point on the wide edge of the construction)

Stringer angle (between the floor and the bottom of the material)

What Affects Your Stair Calculation?

There are a few other things that can be added to your stair calculations, depending on the specifics of your project. Inputting this data can change the dimensions significantly, so make sure you cover all bases.

  • Stringer Mount Type

You must consider whether your stair stringers will have a standard mount or flush mount.

A standard mount is when the last stair tread (the bit you stand on) is one step height below the surface of the next floor. Flush mount means the final tread is on the same level as the landing or floor level.

The mount type you use impacts the total run and the stringer length and height.

  • Stair Tread

Tread means the part of the stair you stand on- a.k.a. the flat surface facing upward on each step. Depending on the type of stairs you are building, the style of tread you use may come into play.

In a deck stair calculator, for example, the tread thickness and whether it is single-board or double-board can alter the measurements.

  • Headroom Restrictions

There are regulations and building codes regarding how much headroom you need above a staircase. If you don't meet the minimum requirement with your proposed measurements, you will need to reassess.

Stair Calculators for Rental Property Owners and Real Estate Investors: How and Why Are They Used?

Using any real estate calculator can make life a lot easier, but few are quite as practical as this one.

Unlike most calculators, which are used to determine financials, a stair calculator helps you double-check that your construction plans are correct, viable, and up to code.

There are a few ways to utilize a stair calculator as a real estate investor or property owner.

  • When you are renovating and want to get it right the first time around
  • To confirm the dimensions on the plan you have are correct
  • As a way to find out how much space will be left once the stairs are in
  • In liability cases where someone claims the stair dimensions are not to code

What Are Good Stair Measurements?

Stairways come in all shapes and sizes, and no set of dimensions is correct for every property.

That said, there are regulations and limitations on what you are allowed to do for safety reasons- including stair width, maximum step height, and minimum tread depth.

Always confirm that you are sticking to the rules before pressing on with construction. Luckily, most good stair calculators will tell you if you have entered a measurement that is outside what building codes allow.

Where Does DoorLoop Come In?

DoorLoop has your back in every part of your property management business. Being a landlord does stop just because renovations are happening- you still have more to think about than the dimensions of your new stairs!

You can use DoorLoop to keep on top of your portfolio, manage ongoing maintenance, and stay in touch with tenants. Once the construction is complete, use DoorLoop to market your property- and find high-quality renters with tenant screening and customizable applications.

No matter what challenges or adventures you face in the real estate and property management world- DoorLoop has an intelligent, convenient, and efficient solution to offer.

From rental property calculators to online rent collection, DoorLoop can help you take your operation to the next level.

Learn more about this comprehensive platform and what it can do for you. Schedule a free demo to explore the possibilities!


The last thing any property owner needs is to start construction and realize something is wrong. With stairs, this can and does happen. Using a stair calculator reduces that risk significantly and can help you plan your stairway project properly!

Frequently Asked Quesitons

David is the co-founder & CMO of DoorLoop, a best-selling author, legal CLE speaker, and real estate investor. When he's not hanging with his three children, he's writing articles here!

Legal Disclaimer

The information on this website is from public sources, for informational purposes only and not intended for legal or accounting advice. DoorLoop does not guarantee its accuracy and is not liable for any damages or inaccuracies.