An extension to file is not an extension to pay tax.
Indiana automatically honors a federal extension (Form 4868) as long as at least 90% of the state and local income tax due has been paid by the original due date. A taxpayer without a federal extension who still needs more time files Form IT-9 and must meet the same 90% payment standard to avoid penalty.
| Item | Detail |
|---|---|
| Form required | None if a valid federal extension was filed and 90% of tax is paid; otherwise Form IT-9 |
| Extension length | Matches the federal extended due date (typically mid-November for calendar-year filers, since Indiana's extended date runs past the federal one) |
| Payment threshold | At least 90% of the state and local income tax due must be paid by the original due date to avoid penalty; interest still accrues on any unpaid balance |
| Authority | IC 6-8.1-6-1; IC 6-8.1-10-2.1; IC 6-8.1-10-7 |