An extension gives you more time to file, not to pay

An extension moves the due date of the return by six months and leaves the due date of the tax where it was. Tax not paid by the original date, April 15, 2026 for a 2025 individual or calendar-year C corporation return, carries interest and a failure-to-pay penalty of 0.5% a month, up to 25%, until it is paid.

Last reviewed September 23, 2026 · Tax year 2026 · Federal and Florida

The extension is automatic and lasts six months. You give no reason, and the IRS contacts you only if it denies the request. It moves the due date of the return, and it "will not extend the time for payment of any tax due on such return".

How to get one

• Individuals file Form 4868 by the original due date, April 15, 2026 for a 2025 return, with an estimate of the year's tax on it. You do not need the form if you pay through IRS Direct Pay, EFTPS or a card and mark the payment as an extension payment; the IRS processes the payment as the extension. The extended due date is October 15, 2026.
• Corporations file Form 7004 by the return's original due date. For a calendar-year C corporation that was April 15, 2026, and the extended date is October 15, 2026. The regulation also makes paying the properly estimated unpaid tax by the original due date a condition of the corporate extension. Partnerships and S corporations use Form 7004 as well.

What still runs from April 15

Interest runs on unpaid tax from the original due date until the day it is paid, and an extension does not change the starting date. The failure-to-pay penalty adds 0.5% of the unpaid tax for each month or part of a month, up to 25%. The penalty can be excused for reasonable cause, and the interest cannot.

For individuals, the regulation presumes reasonable cause in one case. If at least 90% of the tax on your return was paid by the original due date, through withholding, estimated payments or a payment with the extension, and you pay the rest with the return, reasonable cause is presumed for the extension period and the failure-to-pay penalty does not apply. Interest still runs on the unpaid balance.

What the extension saves

A return filed late draws the failure-to-file penalty: 5% of the unpaid tax for each month or part of a month, up to 25%. That is ten times the monthly rate of the failure-to-pay penalty. In a month when both apply, the failure-to-file penalty is reduced by the failure-to-pay penalty, so the two together come to 5%.

An illustration, with round numbers: you owe $10,000 on your 2025 return, pay none of it in April, and file and pay in full on October 15, 2026, six months later.

• With an extension, the return is on time. The failure-to-pay penalty is 0.5% for six months, 3%, or $300.
• Without one, the return is six months late too. The failure-to-file penalty reaches its 25% limit in the fifth month and is reduced by 0.5% in each of those five months, to 22.5%, or $2,250. With the same $300 failure-to-pay penalty, the total is $2,550.

Interest is the same in both cases.

Florida

Florida has no personal income tax, so individuals need no Florida extension. A C corporation with a federal extension files a separate Florida request, Form F-7004, with a tentative tax payment, and the Florida return is extended as well. The Florida Department of Revenue states that this extension does not extend the due date for paying the Florida tax.

If you cannot pay in April

You can still get the extension without paying the balance, and any amount you pay by the original due date comes off the base that interest and the failure-to-pay penalty are figured on. If you file on time, extension included, and have an installment agreement in effect, the failure-to-pay rate for an individual drops to 0.25% a month. How those agreements work is in Can't pay in full? Payment plans and your options.

Sources

1. IRC § 6081, extension of time for filing returns
2. Treas. Reg. § 1.6081-4, automatic extension for individual income tax returns
3. Treas. Reg. § 1.6081-3, automatic extension for corporation income tax returns
4. IRC § 6072, time for filing income tax returns
5. IRC § 6601, interest on underpayment, nonpayment, or extensions of time for payment of tax
6. IRC § 6651, failure to file tax return or to pay tax
7. Treas. Reg. § 301.6651-1, failure to file tax return or to pay tax
8. IRS, 2025 Form 4868, Application for Automatic Extension of Time To File (PDF)
9. IRS, Instructions for Form 7004
10. IRS, Get an extension to file your tax return
11. IRS, Failure to pay penalty
12. Florida Constitution, art. VII, § 5 (no tax on the income of natural persons)
13. Florida Statutes § 220.222, returns; time and place for filing
14. Florida Department of Revenue, Corporate income tax

This article is general educational information, not tax, legal, or accounting advice, and does not create a client relationship. Tax law changes and depends on your specific facts. Information is current as of September 23, 2026 for tax year 2026; verify before acting. Consult a qualified CPA, EA, or attorney about your situation.

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