Tax filing · Form 4868
How to file a tax extension: send the free Form 4868 by April 15 for six more months to file, but not to pay.
An IRS tax extension moves your filing deadline from April 15 to October 15. You do not have to say why. Any tax you owe is still due April 15. Unpaid tax draws interest from then, and usually a late payment penalty.
Updated · Sources
Individual federal returns
- 5%
- a month of the unpaid tax is the late filing penalty, up to 25%. Filing by your extended date avoids it.
- 0.5%
- a month, up to 25%, is the usual late payment penalty on tax unpaid after April 15, extension or not.
- 90%
- of your tax, paid by April 15, removes the late payment penalty on an extension if the rest comes with an on-time return.
A tax extension filed in 2026, for a 2025 return, runs to October 15, 2026. An extension on a 2026 return runs to October 15, 2027.
How do I file an extension with the IRS?
You need an extension only if you will file your return after April 15. Form 4868 is the tax extension form for individuals. If you e-file, you get an acknowledgment; otherwise the IRS writes only if it denies the request.
Estimate your total tax on the extension form
Line 4 asks for the total tax you expect your return to show, worked out from the information you have. Enter zero if you expect no tax at all. If the IRS later finds the estimate was not reasonable, the extension is void.
Subtract what you have paid
You still get the extension if you cannot pay the balance in full. Line 5 is the total payments you expect your return to show, such as withholding, estimated tax and refundable credits. Leave out what you pay with this form. Line 6 is the balance due, and line 7 is what you pay now.
File it online or by mail by April 15
The deadline is your return’s due date, April 15 for most people. You can file online through tax software or a tax professional, or mail the paper form. IRS Free File takes extensions at any income, so anyone can e-file one free.
Pay online and skip the form
You can pay part of your tax online instead, through IRS Direct Pay, your IRS online account or a card. Mark it as an extension payment, and you need no Form 4868. Keep the confirmation number the IRS gives you.
Fiscal-year filers must mail a paper Form 4868. Do not use Form 4868 if you want the IRS to figure your tax. You also cannot use Form 4868 if a court has ordered you to file by the due date.
What an extension and the 90% rule save on an $8,000 balance.
No extension
$2,040
The return is six months late, so a late filing penalty of $1,800 joins the $240 for paying late.
Extension, $8,000 paid October 15
$240
The extension removes the filing penalty. Only $32,000, or 80% of the tax, was paid on time, so the payment penalty stays.
Extension, $4,000 paid by April 15
$0
Paying $4,000 more by April 15 puts $36,000, or 90% of the tax, on time. The last $4,000 goes with the return, and the 90% rule removes the payment penalty.
Both penalties count each month or part of a month after April 15, and October 15 makes six. The payment penalty is 0.5% a month for all six, or 3% of $8,000. While both run, the filing penalty is 4.5% a month instead of 5%, so it reaches 22.5% of $8,000 after five months and stops. A 2025 return filed more than 60 days late also owes at least $525, or the whole tax if that is less. Interest is added in all three cases on tax unpaid after April 15. The rate was 6% a year from April to June 2026, and 7% from July.
How do you file a corporate tax extension?
A business asks for more time on Form 7004, one application per return, sent by the return’s original due date. The dates are for calendar-year 2026 returns.
| Due date | Extended due date | |
|---|---|---|
| Partnership (Form 1065) | March 15, 2027 | September 15, 2027 |
| S corporation (Form 1120-S) | March 15, 2027 | September 15, 2027 |
| C corporation (Form 1120) | April 15, 2027 | October 15, 2027 |
| Sole proprietor (Schedule C) | April 15, 2027 | October 15, 2027 With Form 4868, since Schedule C is part of Form 1040 |
The tax on each of these returns is still due on the first date shown. Estates and trusts on Form 1041 get 5½ months. For 2025 returns, the first two dates were March 16, 2026, because March 15 fell on a Sunday.
What can still cost you on an extension?
Quarterly payments have their own test
The underpayment penalty on estimated tax has its own safe harbor, separate from the 90% rule for extensions. Withholding and on-time quarterly payments meet it if they cover 90% of this year’s tax or 100% of last year’s. The 100% becomes 110% if last year’s adjusted gross income (AGI) topped $150,000, or $75,000 for married filing separately.
Estimated tax dates stay the same
An extension does not move any estimated tax due date. The first payment for the new tax year is due April 15, the same day as last year’s balance.
A state tax extension has its own rules
A California tax extension is automatic, with no form to file, but the tax is still due April 15. New York needs its own Form IT-370, and its extension holds only if you pay the tax you expect to owe.
You live abroad on April 15
A US citizen or resident who lives outside the US and Puerto Rico, with a tax home there too, gets until June 15. You attach a statement to the return saying you qualify, and interest still runs from April 15.
You cannot pay the whole balance
An IRS installment agreement lets you pay over time, and it can lower the late payment penalty to 0.25% a month. The lower rate applies only if you file on time, including any extension. Interest still runs until the balance is paid.
October 15 is the limit
The automatic 6-month extension is generally the most time the IRS can give on an individual return. You can file any time before it runs out.
A CPA firm files your federal extension for free.
Valim files federal extensions free for anyone, whether or not Valim prepares the return: Form 4868 for individuals and Form 7004 for businesses.
- After the extension, we prepare your federal and state returns, and we file most within days of receiving your documents.
- When we are preparing your return, we work out an April 15 payment that aims to cover 90% of your tax.
- We work out next year’s estimated payments using the safe harbor.
- For a business, we work from your bookkeeper’s year-end books to prepare the return that Form 7004 extended.
- We answer IRS or state notices on returns we prepared, such as a penalty notice, within the fee.
- Federal extension
- Free
- Individual return
- from $195
- Business return
- from $495
We quote a flat fee before work starts. We do not bill hourly.
What do people ask about tax extensions?
How do I file a tax extension for free?
You can file a federal tax extension for free through IRS Free File, which takes extensions at any income. You can also mail a paper Form 4868 by April 15. A third way is to pay part of your tax online through IRS Direct Pay and mark it as an extension payment. That payment counts as your extension. Valim files Form 4868 or Form 7004 free for anyone, even if someone else prepares the return.
Is there a penalty for filing an extension on taxes?
No, filing an extension carries no penalty, and the IRS charges no fee for it. The penalties come from paying late or filing late. Tax unpaid after April 15 draws interest, and usually a late payment penalty of 0.5% a month, even on an extension. If you owe tax, filing after April 15 without an extension, or after October 15 with one, adds a late filing penalty. The late filing and late payment penalties together cost 5% of the unpaid tax a month for the first five months.
Does an extension give me more time to pay?
No, an extension moves only your filing date. Form 4868 is not an extension to pay taxes, which are still due by April 15. Anything unpaid after that date is charged interest, and usually a penalty of 0.5% a month. If you cannot pay in full, pay what you can by April 15 to limit the interest. A separate request on Form 1127 can extend the time to pay, but only for undue hardship, and interest still runs.
How much should I pay with my extension?
Pay enough that at least 90% of your total tax is paid by April 15, counting withholding and estimated payments. If you pay the rest with your return, no late payment penalty applies for the extension period. Interest still runs on the unpaid balance from April 15. The estimated tax safe harbor is a separate test, for the penalty on quarterly payments during the year.
How much does it cost to file an extension for taxes?
Filing a federal extension costs nothing, because the IRS charges no fee. Valim files one free for anyone, too. Tax paid after April 15 does cost money. It is charged interest, at 7% a year for the last quarter of 2026, and usually a late payment penalty as well.
Can a business get an extension?
Yes. Most business returns get six more months on Form 7004, filed by the return’s original due date, and Form 1041 gets 5½. Sole proprietors are the exception: their Schedule C is part of Form 1040, which Form 4868 extends. Neither form gives more time to pay.
Sources
- IRS, Form 4868 (2025), Application for Automatic Extension of Time To File U.S. Individual Income Tax Return
- 26 C.F.R. § 1.6081-4, Automatic extension of time for filing individual income tax return
- 26 U.S.C. § 6651, Failure to file tax return or to pay tax
- 26 C.F.R. § 301.6651-1, Failure to file or to pay (reasonable cause on extension)
- 26 U.S.C. § 6654, Failure by individual to pay estimated income tax
- 26 C.F.R. § 1.6081-5, Extensions of time in the case of certain partnerships, corporations and U.S. citizens and residents
- 26 C.F.R. § 1.6161-1, Extension of time for paying tax or deficiency (Form 1127)
- IRS, Get an extension to file your tax return
- IRS, Failure to file penalty
- IRS, Quarterly interest rates
- IRS, Instructions for Form 7004 (Rev. December 2025)
- IRS, Publication 509 (2026), Tax Calendars
- California FTB, Extension to file
- New York State Department of Taxation and Finance, Instructions for Form IT-370 (2025)
Reviewed and updated September 2026. General information, not advice for your situation.