Quick answer

File IRS Form 4868 when you need more time to prepare your federal income tax return. Use a state extension (or the state’s required form/process) when your state requires one—because state extensions are separate legal requests and may have different filing, payment, or approval rules.

How the federal extension (Form 4868) works

  • Purpose: Form 4868 grants an automatic extension to FILE your individual federal income tax return (typically six months). It does not extend the time to PAY any taxes you owe. (IRS: About Form 4868)
  • Deadline: File Form 4868 by the original due date of your return (usually April of the filing year). For most individual taxpayers this means filing 4868 by the federal due date; the extension pushes the filing deadline about six months later. Always confirm yearly deadlines on IRS.gov because dates can shift for weekends/holidays or year-to-year changes. (IRS)
  • Payment: Estimate what you owe and pay as much as possible when you file Form 4868. Interest and failure-to-pay penalties begin accruing after the original due date on unpaid balances. The failure-to-pay penalty commonly starts at 0.5% of unpaid tax per month (up to a limit) and interest is assessed on unpaid tax and penalties. Check IRS penalty guidance for current rates. (IRS)
  • How to file/pay: You can submit Form 4868 electronically (through tax software, a tax pro, or IRS e-file) or by mail in paper form. You can also pay electronically via IRS Direct Pay, EFTPS, debit/credit card, or other IRS payment options when you request the extension. Filing 4868 without payment does not stop accrual of interest or payment penalties. (IRS)

Source: IRS — About Form 4868 (https://www.irs.gov/forms-pubs/about-form-4868)

Why state extensions are different

States control their own income tax rules. A state may:

  • Automatically accept the federal extension (file Form 4868 or notify them) for filing only; or
  • Require a separate state extension form or online request; or
  • Require full or partial payment by the standard filing date even if you file for a state extension.

That means relying solely on a federal extension can expose you to state penalties and interest. Always check your state’s Department of Revenue or tax agency for precise requirements.

Examples of state differences

  • Some states (e.g., those that mirror federal practice in typical years) provide an automatic filing extension when you properly file Form 4868 with the IRS — but still expect payment by the federal due date.
  • Other states require a separate extension request and may charge penalties for unpaid balances even if you receive a filing extension.

For state-specific rules, search your state’s department of revenue website or review published state guides. FinHelp’s related guides that explain filing vs payment differences and state-specific extension topics are useful: When to Use Form 4868: Filing an Extension Correctly and Filing Extensions vs. Payment Extensions: What Taxpayers Need to Know.

Practical steps to coordinate federal and state extensions

  1. Confirm deadlines today: Check the IRS filing deadline and your state’s due date (state deadlines occasionally differ by a day or are extended for certain events). Official sources: IRS.gov and your state Department of Revenue.
  2. Estimate federal and state tax liabilities: Use year‑end statements and recent pay stubs to produce a reasonable estimate. Pay as large an amount as you can by the federal due date to minimize interest and failure‑to‑pay penalties.
  3. File Form 4868 for federal filing relief and, if required, submit your state extension form or online request before the state deadline.
  4. Pay electronically where possible: electronic payments post faster and reduce late-payment risk. Use IRS Direct Pay, EFTPS, or the state’s online payment portal.
  5. If you can’t pay in full, consider an installment agreement both at the federal level (IRS Online Payment Agreement) and at the state level (many states offer installment options). Apply early — states generally have different procedures and credit checks may vary.

In my practice I regularly see clients avoid penalties simply by paying at least 90% of their expected federal tax by the due date and then using an installment agreement for the remainder. That approach minimizes the failure-to-pay penalty and interest while giving time to complete accurate returns.

Common mistakes and how to avoid them

  • Mistake: Filing Form 4868 and assuming state filing and payment deadlines are covered. Fix: Check state requirements and submit separate state forms or payments if necessary.
  • Mistake: Filing for an extension but not paying an estimated tax balance. Fix: Pay at least what you can electronically on or before the due date.
  • Mistake: Waiting until the extended deadline to gather records and then rushing an inaccurate return. Fix: Use the extension to organize records and consult a tax professional if your return has complex items (e.g., business income, capital gains, or rental property).

Special situations

  • Self-employed taxpayers: They may owe both income tax and self-employment tax and should ensure estimated tax payments were made through the year to avoid underpayment penalties.
  • Businesses and trusts: Different extension forms may apply (e.g., Form 7004 for many business returns). Confirm whether your entity needs a different form or process.
  • Disaster or combat zone relief: The IRS and many states may grant additional filing or payment relief in declared disaster areas or for military in combat zones. See FinHelp’s emergency-relief guide for more on those exceptions: https://finhelp.io/glossary/emergency-relief-for-taxpayers-after-natural-disasters-filing-and-payment-extensions/

Checklist before you file an extension

  • Estimate total federal tax due and pay as much as possible before the original due date.
  • File Form 4868 electronically or mail the completed form by the due date.
  • Confirm whether your state requires a separate extension form or payment and act accordingly.
  • Document your payment and confirmation numbers; save copies of submitted forms.
  • If you can’t pay, research installment agreements or temporary relief programs with IRS and your state.

Penalties, interest, and timelines (what to expect)

  • Filing extension removes the late-filing penalty if you file by the extended deadline, but it does not stop interest or failure-to-pay penalties. Interest accrues on unpaid tax from the original due date until paid. The failure-to-pay penalty typically begins at about 0.5% per month on unpaid tax balances and may increase for longer periods. Confirm current penalty and interest rates on IRS.gov as they can change. (IRS)

Final notes and professional disclaimer

Filing Form 4868 is a practical tool to avoid late-filing penalties at the federal level, but it does not relieve payment obligations or automatically resolve state-level rules. In my work as a financial educator, coordinating a payment strategy and checking state guidance before the deadline prevents most surprise penalties.

This article is educational and not individualized tax advice. For specific tax planning or to address complex situations (multi-state income, business filings, international tax issues), consult a qualified tax professional or your state tax agency.

Authoritative sources

  • IRS — About Form 4868: https://www.irs.gov/forms-pubs/about-form-4868
  • IRS — Payments, Penalties and Interest (see IRS.gov for current rates)
  • State Department of Revenue websites (check your state’s official tax site for extension rules)

Internal FinHelp links

Professional disclaimer: This content is for educational purposes and should not be taken as personalized tax advice. For tailored guidance, consult a CPA, enrolled agent, or state tax authority.