There are 89 different forms available on the IRS free-file-forms site. Depending how you count, anyway. Iu2019m excluding u201cadditional statementu201d forms (e.g.: Form 2441 Information statement), separate pages of the same form (e.g.: Form 8949, Page 1 and Page 2), different versions of the same form (e.g.: Schedule C, and Schedule C-EZ), forms normally printed together (e.g.: Form 2210 and Schedule AI), and multiple copies of the same form (e.g; Schedule SE for both spouses). Iu2019ve also excluded Form 4868 and Form 1040-ES, which are not normally filed with the main return.Iu2019m not sure that it is possible to use all 89 forms, as some may apply to mutually inconsistent situations. It would be tough to see how you could file Schedule EIC (Earned Income Credit) while also requiring Form 6251 (Alternative Minimum Tax); as the two have AGI requirements that do not overlap.I would guess it would be theoretically possible to use maybe 80 different forms in one filing, although such a filer would have a very, very interesting life. So would their tax preparer.