Tax Extension Deadline FY 2025-26 | When to File & How to Extend

The Tax Extension Deadline FY 2025-26 lets eligible filers move their filing date from April 15, 2026 to October 15, 2026 by timely submitting Form 4868 or the business equivalent.

At BooksMerge we help busy taxpayers and small business owners navigate deadlines with clarity, so you file on your terms and keep penalties low.

Table of contents

1. What is the Tax Extension Deadline FY 2025-26?

2. Who can request an extension and what it does and does not do?

3. Key dates for individuals and business filers

4. How to file an extension? (Forms 4868 and 7004)

5. Paying taxes when you file an extension — why it matters

6. Common mistakes and how to avoid penalties

7. Quick checklist before October 15, 2026

8. Conclusion

9. FAQ

1. What is the Tax Extension Deadline FY 2025-26?

The Tax Extension Deadline FY 2025-26 refers to the extended filing date granted to taxpayers who submit the correct extension form by the original due date. For most individual calendar-year filers, make the extension request by April 15, 2026 and you get until October 15, 2026 to file your return. This is an automatic extension to file — not to pay.

2. Who can request an extension and what it does and does not do?

Who can request it

• U.S. citizens and residents with Form 1040-family returns can use Form 4868 to request six extra months.

• Many businesses use Form 7004 to extend certain business return deadlines; exact due dates depend on entity type and tax year.

What the extension does

• Gives six additional months to file your return (to Oct 15, 2026 for most 2025 calendar-year returns).

What the extension does not do

• It does not extend the time to pay any tax due. Interest and possible penalties accrue from the original due date if you don’t pay on time.

3. Key dates for individuals and business filers

• April 15, 2026 — File your return or submit Form 4868 by this date to secure an October 15 extension for most individual filers.

• October 15, 2026 — Last day to file your 2025 return if you filed an extension.

• Business deadlines vary — Partnerships and S corps often have different original due dates (commonly March 15, 2026), and Form 7004 must be filed by the return’s original due date to secure the extension. Always check the Form 7004 due date table.

4. How to file an extension? (simple steps)

For individuals (Form 4868)

1. Estimate your 2025 tax liability.

2. File Form 4868 electronically or by mail by April 15, 2026.

3. Pay any tax owed when you file the extension to avoid penalties and interest.

For businesses (Form 7004)

1. Identify the return you need to extend (S corp, partnership, corporation, etc.).

2. File Form 7004 by the original return due date (dates depend on entity).

3. Estimate and pay tax due if required.

Filing electronically is faster and creates an immediate record that you requested the extension.

5. Paying taxes when you file an extension — why it matters?

An extension delays only the paperwork, not your payment obligation. Pay as much as you can by April 15, 2026. Interest starts on unpaid balances at the statutory rate, and failure-to-pay penalties can add up. If paying fully is impossible, consider a short-term payment plan or speak with a tax pro. The IRS emphasizes that extensions do not prevent penalties for unpaid taxes.

6. Common mistakes and how to avoid penalties

Top mistakes

• Filing an extension but not paying estimated taxes.

• Missing the correct due date for business entities because it differs from individual deadlines.

• Assuming an extension covers state tax filings — states often have separate rules.

How to avoid them

• Estimate conservatively and pay something by April 15, 2026.

• Confirm your entity’s original due date before filing Form 7004.

7. Quick checklist before October 15, 2026

• Gather W-2s, 1099s, K-1s, receipts, and bookkeeping records.

• Reconcile business bank statements and payroll reports.

• Revisit any estimated tax payments made in 2025 to ensure accuracy.

• If you need help, contact a professional; BooksMerge offers friendly, practical support at +1-866-513-4656.

• Brush up on small business financial literacy to improve decisions — see our related post for helpful statistics and context: financial literacy statistics

8. Conclusion

Understanding the Tax Extension Deadline FY 2025-26 gives you breathing room to prepare accurate returns. Remember this: extensions buy time, not forgiveness. File Form 4868 or Form 7004 on time, pay what you can, and use the extended window to gather clean records. If you want personalized help, BooksMerge can guide you step-by-step at +1-866-513-4656.

FAQs

Q1: When is the tax extension deadline for 2025?
A: File Form 4868 by April 15, 2026 to extend filing to October 15, 2026 for most individual filers.

Q2: Does the tax extension deadline 2026 change payment deadlines?
A: No. The extension to October 15, 2026 applies only to filing. Payment is still due by the original due date (April 15, 2026) to avoid penalties and interest.

Q3: What is the business tax extension deadline 2025?
A: Business extension deadlines depend on the return type. File Form 7004 by the original due date of the return; partnerships and S corps often have March 15, 2026 deadlines, while some corporations use April 15, 2026. Check Form 7004 instructions.

Q4: How do I file an IRS extension 2025 online?
A: You can e-file Form 4868 through commercial tax software or tax professional channels, or use IRS Free File when available; pay any balance due electronically.

Q5: What is the deadline to file tax returns that received extensions?
A: Generally, the deadline to file extended 2025 returns is October 15, 2026, provided you filed the extension by the original due date.