A tax extension gives you more time to file your return - it does not give you more time to pay any tax owed. This distinction is the most important thing to understand about extensions. Filing an extension without paying the estimated tax due results in failure-to-pay penalties and interest accruing from the original due date.
An extension extends the time to FILE. It does not extend the time to PAY. Any tax estimated to be owed must be paid by the original due date (April 15 for individuals). Interest under IRC §6601 accrues from the original due date on any unpaid balance. The failure-to-pay penalty under IRC §6651(a)(2) is 0.5% per month on the unpaid balance. Filing an extension does not eliminate either.
| Form 4868 DOES | Form 4868 DOES NOT |
|---|---|
| Extend the time to file Form 1040 to October 15 | Extend the time to pay any tax owed |
| Prevent the failure-to-file penalty (5%/month, max 25%) if filed timely | Prevent interest accruing from April 15 on unpaid balance |
| Give additional time to gather documents (K-1s, foreign account statements, brokerage consolidations) | Extend state tax return deadlines in most states (check your state) |
| Extend time for IRA contributions - IRA contributions for 2025 are due April 15, 2026 regardless of extension | Extend time for HSA contributions - same deadline as IRA |
| Require no reason or explanation - the extension is automatic if filed timely | Require a minimum payment - you can file Form 4868 with $0 payment if you genuinely owe nothing |
Form 4868 can be filed electronically through IRS Direct Pay, through tax software, or through a tax preparer. It can also be filed by mailing a paper Form 4868 (must be postmarked by April 15). Electronic filing is strongly preferred - you receive immediate confirmation. The form requires only your name, address, Social Security number, estimated total tax liability, total payments already made, and estimated balance due.
You do not need a reason to file an extension. The IRS grants extensions automatically when Form 4868 is filed timely. There is no approval process and no response from the IRS unless you owe money and did not pay.
Form 7004 covers extensions for all business entity returns: 1120 (C-corp), 1120-S (S-corp), 1065 (partnership), 1041 (trust/estate), and others. Like Form 4868, it is automatic when filed timely. Unlike Form 4868, the extended deadline varies by return type.
| Return Type | Original Due | Extended Due | Extension Length |
|---|---|---|---|
| Form 1065 (Partnership) | March 16, 2026 | September 15, 2026 | 6 months |
| Form 1120-S (S-Corp) | March 16, 2026 | September 15, 2026 | 6 months |
| Form 1120 (C-Corp, calendar year) | April 15, 2026 | October 15, 2026 | 6 months |
| Form 1041 (Trust/Estate) | April 15, 2026 | September 30, 2026 | 5.5 months |
| Form 990 (Exempt Org.) | May 15, 2026 | November 16, 2026 | 6 months |
States generally fall into one of three categories regarding extensions:
Automatic federal conformity: Most states (including New York and Florida) automatically honor the federal extension. If you file Form 4868 federally, your state return is also extended without filing a separate state form. However, payment of any state tax estimated to be owed is still due by the original state deadline.
Separate state extension required: Some states require filing their own extension form regardless of the federal extension. California (Form FTB 3519), Massachusetts, and a handful of others require a separate filing or payment by the original due date to avoid state penalties.
States with no income tax: Florida, Texas, Nevada, Wyoming, South Dakota, Alaska, Washington (no individual income tax), Tennessee, and New Hampshire - no state income tax return, no state extension issue.