October 15 — Individuals
If you have an automatic 6-month extension to file your income tax return for 2013, file Form 1040, 1040A, or 1040EZ and pay any tax, interest, and penalties due - Details
October 15 — Partnerships
Electing large partnerships: File a 2013 calendar year return (Form 1065-B). This due date applies only if you were given an additional 6-month extension - Details