I would have the architect figure that out. Are you paying them to draw up your plans or help design them too?

The horizontal distance will be about 17 feet. Taller ceilings make the stairs longer.

Using a 10" tread cut, it comes out to 180" of floor space. The stringers are 20 ft pieces of wood. Special order. Ca-ching.
Casey

MFatt,
I want to have the plan totally debugged (as much as possible) before I give them the plan.
Sombreuil,
Thanks! What is the rise height?
Bus driver,
What is your tread count and size and rise height?
Thanks

Just found this link. Of Course there are many more out there.

Here is a link that might be useful: Stairs

For a riser ht of 7.33 and a tread run of 10 the total run would be 14-2. 18 Risers and 17 Treads

Renovator,
OK so, 11ft x 12" = 132"
132" / 7.33 In = 18 -1 for thread count = 17
17 x 10" = 170" /12 in = 14.2 ft.
Got it.
Thanks!

I used 7 3/8 rise and 11 1/2 tread. The combination of your building code and personal preference could differ from that. But your preferences are very unlikely to result in a longer horizontal distance than 17 feet. Going shorter is easy, changing to longer later in the design process will not necessarily be easy.

This post was edited by bus_driver on Sat, Sep 20, 14 at 19:07

Some might like a 10.5 tread with a 7.33 riser. The tread will get an inch larger when the nosing is added.

The link listed below is one of the best calculators I've ever used.

Here is a link that might be useful: Stair Calculator

Thanks!