If you have decided to create a tri-fold brochure (3 panels) you will have to create a different measurement for each panel. For an 8.5×11 letterfold brochure, the 1st and 2nd panels will measure 3 11/16″ and the 3rd panel will measure 3 5/8″. Your margin should be at least 3/8″ on the top, bottom, right and left sides.
Use this link to get a sample of the measurements drawn out… https://www.dropbox.com/sh/jvu8t1tjyqe9bch/CuPw74mb-M
