2026 Small Business Tax Deadlines Calendar

Key Takeaways

• January 31, 2026 is the deadline to mail Form 1099-NEC to contractors and file with the IRS to avoid tiered late penalties.
• March 16, 2026 marks the deadline for S-Corporation and Partnership returns (Form 1120-S and 1065) or extension requests.
• April 15, June 15, Sept 15, and Jan 15 are the big four dates for quarterly estimated tax payments for solo owners and corporations.
• March 16, 2026 is also the final day to file Form 2553 to elect S-Corp status for the 2026 tax year.

Conventional wisdom says you should wait until April to think about your taxes. Here's why that's wrong for most small owners: by April, you've already missed the chance to elect a more favorable tax structure for the current year, and you're likely staring at a massive underpayment penalty for skipping your quarterly vouchers.

A landscaping company in Georgia recently paid $2,400 in preventable interest because they ignored the June and September estimated tax windows. The IRS doesn't view taxes as an annual event; they view them as a "pay-as-you-go" obligation. If you don't pay as you earn, you're effectively taking an unauthorized loan from the government, and they charge high interest rates for the privilege.

First Quarter: The January Sprint

January is the most dangerous month for your mailbox. You aren't just filing your own returns; you're responsible for reporting what you paid others.

• January 15, 2026: Final 2025 estimated tax payment due. If you haven't paid enough throughout the previous year, this is your last chance to blunt the underpayment penalty.
• January 31, 2026: Deadline for 1099-NEC and 1099-MISC. If you paid a contractor more than $600 in 2025, the form must be in the mail to them and filed with the IRS by today. See the IRS guide on 1099-NEC for specific filing requirements.
• January 31, 2026: Form 941 (Employer's Quarterly Federal Tax Return) for Q4 2025 is due.

Second Quarter: The S-Corp Shift

March and April are when the big money moves. This is also when most businesses decide whether they want to Ditch Self-Employment Tax with an S-Corp Election.

• March 16, 2026: S-Corp (1120-S) and Partnership (1065) tax returns due.

If you can't file, you must submit Form 7004 for a six-month extension today. This is also the deadline to file Form 2553 to be taxed as an S-Corp for the 2026 calendar year.

• April 15, 2026: Individual 1040 returns and C-Corp 1120 returns due. Even if you get an extension to file the paperwork, you must pay any taxes owed today. The extension only applies to the forms, not the money.
• April 15, 2026: Q1 2026 Estimated Tax payment due. Use Form 1040-ES to calculate this. Gov/tax-calendar) to verify specific local nuances if you operate on a fiscal year rather than a calendar year.
• June 15, 2026: Q2 2026 Estimated Tax payment due. This is the one most owners forget. For more on how to avoid these traps, read Avoid IRS Penalties: Use the Safe Harbor Rule for Q2 Taxes.

Third Quarter: The Summer Lull (Is a Trap)

While business might slow down in July and August, the IRS expects their cut by mid-September.

• September 15, 2026: Q3 2026 Estimated Tax payment due.
• September 15, 2026: Final deadline for extended S-Corp and Partnership returns. If you filed an extension in March, your time is up today.

Fourth Quarter: Year-End Clean Up

• October 15, 2026: Final deadline for extended Individual and C-Corp returns.
• December 31, 2026: Last day to make 401(k) contributions or equipment purchases for 2026 tax deductions. For those looking to lower their bill, Claim SBA Fee Waivers: New 2026 Credits for Rural Startups might offer additional ways to keep capital in the biz.

State-Specific Deadlines to Watch

Most states follow the federal April 15/October 15 calendar, but payroll and sales tax vary wildly.

1. California: FTB Form 3522 (LLC Tax) is usually due by the 15th day of the 4th month of your taxable year.
2. Texas: Franchise Tax reports are generally due May 15.
3. Delaware: Franchise Tax for Corporations is due March 1; LLC fees are due June 1.
4. Florida: Annual Reports must be filed by May 1 to avoid a $400 late fee.
5. New York: Income tax follows federal dates, but Sales Tax filings often occur quarterly on the 20th of the month following the quarter's end.

The 2026 Master Deadline Checklist

Copy this list and stick it on your office wall. Missing these by even one day can trigger penalties that wipe out a month of profit.

Date	What's Due?	Form	Who Needs It?
Jan 15	Q4 2025 Estimated Tax	1040-ES	Solo/LLC Owners
Jan 31	Contractor Reporting	1099-NEC	Your Contractors
Mar 16	S-Corp/Multi-Member LLC	1120-S / 1065	IRS
Mar 16	S-Corp Election	2553	New S-Corps
Apr 15	Individual Tax Return	1040	Everyone
Apr 15	Q1 2026 Estimated Tax	1040-ES	Solo/LLC Owners
June 15	Q2 2026 Estimated Tax	1040-ES	Solo/LLC Owners
Sept 15	Q3 2026 Estimated Tax	1040-ES	Solo/LLC Owners
Jan 15, '27	Q4 2026 Estimated Tax	1040-ES	Solo/LLC Owners

Don't rely on your memory. Set calendar alerts for one week before each of these dates. If you find your bookkeeping is too messy to meet these deadlines, it might be time to Ditch the Spreadsheet for a CRM or an automated accounting tool to stay current. Taxes are the largest expense most small businesses have, treat these dates with the same respect you give your biggest client's deadline.

Related free tool

Quarterly Estimated Tax Estimator, Get your per-quarter number in 60 seconds. Free, no signup to start.

---

📋 Disclaimer

This article is for informational purposes only and doesn't constitute legal, tax, financial, or professional advice. Laws and regulations change frequently, and the information presented may not reflect the most current legal developments. Always consult with a qualified professional (CPA, attorney, financial advisor) before making business decisions based on this content. MyBizNerd may receive compensation through affiliate links, but this never influences our recommendations.

---