Quick overview

Requesting an extension gives you extra time to prepare and submit your tax return, but it is not a waiver of payment. For most individual taxpayers, the federal extension process is automatic when you properly file Form 4868 and pay any estimated tax by the original return due date. States vary: some automatically honor the federal extension, others require a separate state form or payment.

(Authoritative sources: IRS Form 4868 instructions and payment pages; state Department of Revenue sites.)

How the federal extension works

  • What it does: Filing Form 4868 (Application for Automatic Extension of Time To File U.S. Individual Income Tax Return) generally gives individuals up to six additional months to file (typically moving an April due date to mid‑October). The extension applies only to filing—not to payment. (IRS Form 4868: https://www.irs.gov/forms-pubs/about-form-4868)

  • What it doesn’t do: You still must pay any tax you owe by the original due date to avoid the failure-to-pay penalty and interest. The failure-to-file penalty is generally larger than the failure-to-pay penalty, so filing the extension helps reduce the larger filing penalty but leaves the payment obligation in place. (IRS penalties: https://www.irs.gov/payments/penalties)

  • How to submit it: File Form 4868 electronically through tax software, a tax pro, or the IRS Free File service. You can also mail a paper Form 4868, but electronic filing is faster and gives immediate acknowledgement that the IRS received the extension request. If you pay electronically at the time you file the extension, use IRS Direct Pay, EFTPS, or the IRS payment portal. (IRS Direct Pay: https://www.irs.gov/payments/direct-pay)

  • Paying with the extension: Estimate taxes owed and make a payment when you submit Form 4868. Use the electronic options above or include a payment voucher if mailing a paper form. If you underpay, you may owe interest plus a failure-to-pay penalty (usually 0.5% per month on the unpaid balance, and a higher rate for long-term delinquency). Interest rates change quarterly. (IRS penalties & interest: https://www.irs.gov/payments/penalties)

How state extensions differ

  • No single rule: Each state sets its own rules. Some states automatically grant the same extension period the federal government gives if you filed Form 4868 and paid what you owe to the state. Others require a separate state form and/or a payment with the extension request. A few states don’t allow an extension without a valid reason.

  • Example differences: California and New York both have state extension procedures, but their forms and payment rules differ. Always confirm requirements on your state Department of Revenue or Franchise Tax Board site. (For an overview of state differences, see NASBA’s state extension info: https://www.nasba.org/wp-content/uploads/2019/12/State-Extension-Filing-Information-Updated-12-2019.pdf)

  • Practical step: Visit your state’s tax website and search for “extension” or “extend filing deadline” (e.g., California FTB, NY Dept. of Taxation and Finance). Many states provide online payment portals that let you estimate and remit an extension payment immediately.

Step-by-step: Request a federal extension (practical checklist)

  1. Gather last year’s return and any W‑2s, 1099s, or K‑1s you already received.
  2. Estimate your 12‑month tax liability as best you can. Err on the conservative side: underpaying increases penalties.
  3. File Form 4868 electronically (or mail the paper form) before the original due date.
  4. Pay your estimated tax due when you file the extension using Direct Pay, EFTPS, or debit/credit card.
  5. Keep proof of filing and payment confirmation. Electronic proof is easiest to store.
  6. Use the extension time to complete and file your return by the extended due date.

Step-by-step: Request a state extension (practical checklist)

  1. Check your state DOR website for extension guidance and the correct form. Search your state name + “tax extension.”
  2. Confirm whether your state accepts the federal Form 4868 or requires a different form or online filing.
  3. If a payment is required, make it by the federal tax filing due date to avoid state penalties.
  4. Save confirmation screenshots or paper receipts from the state payment/extension submission.

For a concise how-to on filing extensions, see our practical guide: How to File a Tax Extension. For guidance comparing Form 4868 and state procedures, see When to File Form 4868 vs Request an Extension for State Taxes.

Common scenarios and examples

  • Self‑employed taxpayer: You missed some 1099‑NEC statements and need time to reconcile income. File Form 4868 and pay an estimated tax amount to minimize penalties. Use bookkeeping reports to estimate income if year-end statements are delayed.

  • Out-of-country taxpayer: U.S. citizens and resident aliens living abroad often have different automatic filing deadlines. If you still need more time, Form 2350 may provide an extension when you are awaiting foreign earned income exclusion qualifications. (Form 2350 reference: https://www.irs.gov/forms-pubs/about-form-2350)

  • Business returns: Corporations and certain business returns cannot use Form 4868. Instead, use Form 7004 to request an extension for many business tax returns. (Form 7004 reference: https://www.irs.gov/forms-pubs/about-form-7004)

Common mistakes to avoid

  • Assuming an extension equals more time to pay. It doesn’t. Pay by the original due date.
  • Not estimating conservatively. Underpayment creates penalties and interest.
  • Missing state-specific rules. Treat the federal extension and any state extension as separate tasks until you confirm otherwise.
  • Failing to keep proof of submission. If there’s a dispute later, you’ll want an electronic confirmation or mailed proof.

Penalties, interest, and realistic expectations

  • Failure-to-file penalty: Generally 5% of the unpaid tax per month (or part of a month) up to 25%.
  • Failure-to-pay penalty: Generally 0.5% per month on the unpaid tax (can increase under certain circumstances).
  • Interest: Charged on any unpaid tax from the original due date until the balance is paid; rates change quarterly and are published by the IRS.

Because failure-to-file penalties can add up quickly, filing an extension can reduce the most severe penalty—even when you can’t pay in full. But filing the extension without a payment doesn’t stop interest on the unpaid balance.

(See IRS penalties & interest details: https://www.irs.gov/payments/penalties)

Professional tips from practice

  • Start early with estimated taxes: I advise clients to review quarterly records in March and again in early April to reduce surprises when filing. In my practice, an early conservative estimate and payment often eliminates both penalties and client anxiety.

  • Use electronic payments and get confirmations: Electronic payments (Direct Pay, EFTPS, or IRS gateways) post quickly and provide a timestamped record.

  • If you can’t pay in full: Contact the IRS about payment options. The IRS offers installment agreements and may accept an Offer in Compromise in limited circumstances. Filing the extension and communicating with the IRS can reduce penalties from a worst‑case outcome. (IRS payment plans: https://www.irs.gov/payments)

Final checklist before you file

  • Did you estimate and pay any tax due by the original deadline? (Yes/No)
  • Did you file Form 4868 or your state extension form before the deadline? (Yes/No)
  • Did you save proof of filing and payment? (Yes/No)
  • Do you know your new filing deadline and have a plan to finish your return before then? (Yes/No)

Professional disclaimer: This article provides general information for educational purposes and does not constitute tax advice. Tax rules change and individual circumstances vary—consult a qualified tax professional for personalized guidance.

If you need a step-by-step walkthrough or help estimating a safe extension payment, consider working with a licensed tax preparer or CPA. For more reading on related topics, see our detailed guide on “How to File a Tax Extension” and our comparison of federal vs. state extension rules linked above.