Build Your Own House

Designing Stairs

Designing Stairs With Stair Calculator

Summary: For designing stairs, here is a stair calculator for simple interior staircases. Avoid stair design problems even professional home designers make.

Hello Carl,

I've been reading your book, and learning lots!

I was trying to find the average length/run of a stairway.

I'm in the designing process and I want to know how many horizontal feet to allow for the stairs in my plans.

Thank you for your help!


Hi Christine,

You are wise to take the time to figure the horizontal length of a stair run.

Even professional designers can make mistakes on stair runs.

I have had a couple of new home plans drawn where the stairs did not work out as drawn.

It created problems that were difficult to solve on the job.

Had I not had very skilled carpenters who caught the problem early, the problems would have been even greater.

I found a little on line calculator from EZ Stairs, Inc. EZ Stairs is a stair building kit that helps you build stairs the right way. Check EZ Stairs out. To use their calculator, click here.

Stair design problems usually stem from a desire to save space and keep the size of the house from growing.

Although I am always preaching that size equals cost, trying to squeeze stairs in where there is really not enough room is NOT the way to keep size down. Keep that in mind.

I have seen finished houses where the stairs were too tight either at the top or bottom or at the “winder” (turn) if there was one, making it impossible to get large furniture up the stairs.

Watch head room and riser height carefully and consult with your building inspection department for stair codes.

The building inspection department will turn down a stairway if it violates code requirements...I have had it happen.

Carl Heldmann