Exterior stair bottom rail clearance
 

What is the tallest distance I can go from the stair nose to the bottom of the bottom rail

Need to go back and add your location to your profile.
Differant locations can have differant codes there using.
What rail are you talking about? The hand rail.
Is this inside or outside?
Here's some general rules, may want to check with your local building dept. to verify.
http://inspectapedia.com/Stairs/Stair_Codes.htm

If you are talking about the hand rail keep in mind the hand rail must return back to the wall (so an artical of clothing does not get caught on it)
And must be gripable. How many times have we all seen a hand rail on a deck that is just a 2 X 4 laying flat, that's not legal, it's to wide. Fine to do that but in addition you need one that's grippable.

You're are right Joe. What bothers me about some codes is how humans managed to survive without become extinct without them. I know decks that were built with 2x4 rails for forty years. I began to feel this way when I found out, from someone who wrote electrical codes, that some codes are written, not from a safety standpoint, but by companies with another agenda. I'm sure you can think of a few.

I disagree with you Duck. I read the NEC from front to back, and it is one of the most common sense pieces of writing that I have ever read. Take the rule that there must be an outlet 6 feet from an opening. Based on the typical lamp cord of 6 feet. I remember people running lamp cords on the floor across openings when I was young. That was in older homes with electric added after the fact of course. (Giving away my age here)

Same with the National Plumbing code. Its good, and based on common sense and experience.

What good is a hand rail you cant grab if you slip?

+1 to Jagans

stair rail bottom clearance
 

Rail clearance if you mean the distance gap is to be not more than 4 inches.
Regarding other posts of codes
My opinion.
Codes are generated based on injuries but I believe many have been over done and there should be a point when "they said by now it should be sufficient and we got it right" Anyone can partition for code changes some make sense and others are over the top. Ok tamper resistant electrical outlets for example. Designed to prevent one from inserting an item in an electrical outlet Can we design everything to be safer yes but everything is at a cost. People will say if one life is saved it is worth it? maybe yes maybe no. The line has to be drawn as the code books just be getting thicker. Building standards in fire areas of California prevent rafter block venting and require tempered glass windows but allow raised foundation crawl area venting? Houses so tight they can't breath and no require mechanical venting?

in most places i have worked it is 34-38 inches measured vertically (plumb) from nose to top of handrail. what happened to post number 1?

from the 2009 IRC.

Andy.

Companies can change a code to get you to buy something?? lol

Houses on the Jersey shore that were built to old codes are gone while new code houses right next door need the sand swept from the driveway.
Codes are written as we learn and advance ourselves.
Has nothing to do with anyone trying to make a buck.