Free Stair Stringer Calculator

By Todd Fratzel on Finish Carpentry, Framing

Stair Stringer Calculator – Spreadsheet

Stair Stringer CalculatorRecently I wrote an article about how to build stairs. Since then I’ve had inquiries about some type of calculator or spreadsheet to quickly calculate the rise and run measurements for the stringers. So I sat down and put together a quick Excel spreadsheet that helps you calculate the total number of risers, riser height and tread run.

You can download the FREE Stair Calculator here. All I ask is that you check with your local building officials to make sure you’re following the applicable building codes. Also, if you share it with others please leave the website address on it.

How To Use Stair Stringer Calculator

The free stair stringer calculator / spreadsheet is really easy to use. However, before you begin you’ll need to track down some information. You will need to following information:

  • Total Height of Stairs Required – This should be the height from one finished floor to the other finished floor, measured vertically (plumb).
  • Local Maximum Riser Height – This is the maximum riser height allowed by the building code. Be sure to check with your local building code official to be sure you’re current. Typically this number ranges from 7 inches to 8 inches.
  • Local Minimum Riser Height – Again the building code will specify a minimum riser height.
  • Local Minimum Tread Depth (run) – This is the minimum tread depth allowed by code. This is measured from the face of the riser to the face of the adjacent riser without the tread nose.
  • Local Minimum Tread Overhang – This is the minimum nosing overhang measured from the face of the riser to the front edge of the nosing. This is typically limited by the building code.
  • Local Maximum Tread Overhang – This is the maximum nosing overhang measured from the face of the riser to the front edge of the nosing. This is typically limited by the building code.

Once you have this information you simply enter it into the stair calculator in the blue boxes. The spreadsheet will calculate the rise and run for the stringers and show that information in the yellow boxes. It’s really as simple as that.

Stair Building Materials

Once you’ve figured out the stair geometry you should figure out what materials you’re going to use for the stairs. Stairs can be as simple as 2×12 stringers with plywood risers and treads and as complicated as steel stringers and beautiful hardwood treads.

If you plan on using wood stringers then I would recommend you at least use 2×12 lumber. Today most all stairs that I build end up using 11-7/8″ TimberStrand stringers. They are much stronger than traditional lumber and less likely to split at the apex of the tread/riser cut.

Stair Building Books

Building Stairs by Andy EngelCheck out the following books if you’re looking for some great references for your library.

Building Stairs (For Pros by Pros)

Stair Builders Handbook

Basic Stairbuilding

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About the author

Todd Fratzel

I'm full time builder for a large construction company in New Hampshire. I run their design-build division that specializes in custom homes, commercial design-build projects and sub-divisions. I'm also a licensed civil and structural engineer with extensive experience in civil and structural design and home construction. My hope is that I can share my experience in the home construction, home improvement and home renovation profession with other builders and home owners. I'm also the Editor-in-Chief and Founder of Tool Box Buzz. Please feel free to contact me if you have any questions, suggestions or you'd like to inquire about advertising on this site.

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  1. lottery online says:

    Nice blog. Thats all.

  2. The Writer's Life says:

    There are a number of primitive stair stringer calculators available on the internet. However, this one looks much more detailed; great job!

    Keep up the good work,

    Stair Bracket – GoPro Construction

  3. tina says:

    hope this stair calculator works. My husband has racked his brain to make the stairway in our new house have a landing without cracking your head on the floor upstairs. will let you know the outcome. Thanks.

  4. Warren Geffre says:

    Thanks for the advice on stair building, hopefully I don’t mess this up… :)

  5. thanks says:


  6. Marcus Owens says:

    Thanks for the help I have a 2nd story deck which was to be a fire exit. This will encourage me to try again on the stairs.

  7. Jay Schwartz says:

    I like this site. However, I have a question about the calculator. The code requirement in my city states that “The largest tread width or riser height and nosing depth cannot exceed the smallest by 3/8”. Does this really mean I have to minutely calculate the riser height from the ground to the deck level. All the calculators seem to have the first step close to an inch lower in rise compared to the remaining step risers

    • Todd Fratzel says:

      Yes, you must have all steps within that 3/8″. Those calculators are helping offset the flooring depths, the stringer cuts are not the final step heights.

  8. Harold Blaisdell says:

    Is there any way that this calculator could be used for a dollhouse stairs?

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