Updated for tax year 2025
If you’re a small business owner who filed a tax extension earlier this year, it’s crunch time to finish your return. But there’s no need to stress — you still have time to meet your business tax extension deadline, and TaxAct® can help you get there. Check out our small business extension tax filing page for details.
Whatever your situation (maybe you run a sole proprietorship, manage a team under an S corporation, or operate as part of a partnership), it’s important to know precisely which tax forms you need, your tax year filing due date, and what tax deductions are available. TaxAct Business can help you with all of this and more.
Even if you used a different provider to submit your business tax extension, you can still finish filing your federal income tax return with TaxAct and avoid last-minute stress. Filing after your extended due date can lead to failure-to-file penalties, so it’s important to wrap everything up before the extension deadline.
At a glance
- For partnerships, S corporations, and multi-member LLCs taxed as partnerships, the extended filing deadline is generally Sept. 15, 2026, if you filed Form 7004 on time.
- For sole proprietors, single-member LLCs, and calendar-year C corporations, the extended filing deadline is generally Oct. 15, 2026 (Form 4868 for sole props; Form 7004 for C corps).
- An extension gives you more time to file, not to pay. Always pay estimated tax by the original due date to help avoid penalties and interest.
- You can finish an extended return with TaxAct even if you originally filed your extension elsewhere.
When are business taxes due in 2026 if you filed an extension?
For most calendar-year filers, the extended deadline is Sept. 15, 2026 (partnerships and S corporations) or Oct. 15, 2026 (sole proprietors and calendar-year C corporations). But your exact business tax extension deadline depends on the type of business you run:
| Business type | Original business tax return deadline | Extension request form | Extended due date |
| Sole proprietorship (filing Schedule C with an individual income tax return) | April 15, 2026 | Form 4868 | Oct. 15, 2026 |
| Partnership or LLCs taxed as partnerships | March 16, 2026 | Form 7004 | Sept. 15, 2026 |
| S corporations (S corps) | March 16, 2026 | Form 7004 | Sept. 15, 2026 |
| C corporation (C corps) | April 15, 2026 | Form 7004 | Oct. 15, 2026 (calendar-year filers) |
Tax tip: If your original due date was March 15 or April 15 and you requested a filing extension, your extended tax filing deadline will be either Sept. 15 or Oct. 15 — unless that date lands on a weekend or holiday, in which case the next business day applies. See IRS Publication 509 for the full calendar, including info for fiscal-year filers.
What forms do I need to file after a small business tax extension?
The IRS forms you’ll need depend on your business entity type:
- Sole proprietorships – Schedule C attached to your individual income tax return (Form 1040). Request more time to file with Form 4868.
- Partnerships – Form 1065, plus Schedule K-1 for each partner to report their share of business income. Request more time with Form 7004.
- S corps – Form 1120-S, plus Schedule K-1 for each shareholder. Request more time with Form 7004.
- C corps – Form 1120 for corporate tax returns. Request more time with Form 7004.
- LLCs – Varies depending on whether the limited liability company is taxed as a sole proprietorship, partnership, or corporation.
Need a hand gathering what you need? Check out our helpful tax preparation checklists. We have a checklist for each business type so you can stay organized and ensure you’re ready to file. For original and extended deadlines by entity type, see our key tax deadlines for small business owners.
Tax tip: Remember, filing Form 7004 or Form 4868 only extends your time to file, not to pay. If you still owe tax, you may face penalties and interest on the unpaid balance from the original due date.
Tips for filing your extended business return on time
- E-file for faster tax refund processing and quicker confirmation that your electronic filing was received.
- Double-check your estimated tax payments to ensure they’re applied correctly.
- Don’t forget employment tax and quarterly tax requirements (if applicable).
- If your deadline falls on a weekend or holiday, remember the next business day rule.
- Make sure all taxpayers listed on the return sign before submitting.
FAQs
The bottom line
Your extension deadline — typically Sept. 15 or Oct. 15, 2026, depending on entity type — is your final chance to submit your federal tax return while avoiding avoid failure-to-file penalties. Whether you’re filing as a sole proprietorship, partnership, S corporation, or C corporation, knowing your business tax deadlines and required tax forms will help you wrap up this tax season without any added stress.
TaxAct can help you finish your tax filing quickly and accurately — even if you filed your extension request elsewhere. Ready to check “file my business tax return” off your to-do list before the last day? Let TaxAct Business help you file your return.
This article is for informational purposes only and not legal or financial advice.
All TaxAct offers, products and services are subject to applicable terms and conditions.
Citations
TaxAct. “Need to File a Business Tax Extension? TaxAct Can Help.” TaxAct, 2026.
Internal Revenue Service. “Publication 509 (2026), Tax Calendars.” IRS.gov, 2026.
Internal Revenue Service. “About Form 4868, Application for Automatic Extension of Time to File U.S. Individual Income Tax Return.” IRS.gov, 30 Mar. 2026.
Internal Revenue Service. “About Form 7004, Application for Automatic Extension of Time To File Certain Business Income Tax, Information, and Other Returns.” IRS.gov, 30 Mar. 2026.
Ponder, Meghen. “Key Tax Deadlines for Small Business Owners.” TaxAct Blog, 22 Nov. 2025.
TaxAct. “Tax Prep Checklists.” TaxAct, 2026.
