The key 2026 U.S. federal tax deadlines for businesses are January 15 (Q4 2025 estimated tax), January 31 (Forms W-2, 1099-NEC and 940), March 16 (partnership and S corporation returns), April 15 (individual and C corporation returns plus Q1 estimated tax), June 15 and September 15 (estimated taxes, plus extended pass-through returns in September), October 15 (extended individual and C corporation returns), and April 30, July 31 and October 31 for quarterly Form 941 payroll returns.
International businesses operating in the U.S. face a calendar of federal, state and payroll deadlines that can trigger penalties when missed. This guide summarizes the key 2026 filing dates corporate teams should monitor, from entity-level returns and information reporting to employer filings and estimated payments.
| Date | Deadline | Main forms |
|---|---|---|
| January 15, 2026 | Q4 2025 estimated tax payment | Form 1040-ES |
| January 31, 2026 | Year-end employer filings for 2025 | Forms 940, W-2, 1099-NEC |
| March 16, 2026 | Partnership and S corporation returns for 2025 | Forms 1065, 1120-S, Schedule K-1, Form 7004 |
| April 15, 2026 | Individual and C corporation returns for 2025, Q1 2026 estimated taxes | Forms 1040, 1120, 1040-ES / 1120-W, 4868 / 7004 |
| April 30, 2026 | Q1 2026 payroll return | Form 941 |
| June 15, 2026 | Q2 2026 estimated tax payment | Form 1120-W / 1040-ES |
| July 31, 2026 | Q2 2026 payroll return | Form 941 |
| September 15, 2026 | Extended partnership and S corporation returns, Q3 2026 estimated taxes | Forms 1065 / 1120-S, Schedule K-1, 1040-ES / 1120-W |
| October 15, 2026 | Extended individual and C corporation returns for 2025 | Forms 1040, 1120 |
| October 31, 2026 | Q3 2026 payroll return | Form 941 |
This date marks the final estimated tax payment for the 2025 tax year. It applies to individuals whose income isn’t fully covered by withholding, such as dividends, investment gains or business income.
Forms to file:
Action: Submit your Q4 2025 estimated payment through irs.gov/payments. Review your year-end numbers to ensure your 2025 payment obligations are met before filing season begins.
💡 Key point: Paying on time avoids underpayment penalties and keeps your 2025 tax record clean heading into 2026.
The end of January is one of the busiest periods for employers. Companies must finalize 2025 payroll reporting by filing required returns and issuing year-end statements to employees and contractors.
Forms to file:
Action: File all required payroll returns, and issue W-2s and 1099-NECs.
💡 Key point: Timely, accurate reporting ensures a smooth transition into the 2026 payroll cycle.
This deadline applies to partnerships and S corporations on a calendar year. These pass-through entities report income to owners rather than paying federal income tax directly.
Forms to file:
Action: File your 2025 pass-through return or submit an extension to September 15, 2026. Deliver Schedule K-1s to owners so they can prepare their personal filings.
💡 Key point: Filing on time prevents delays in partner or shareholder individual returns.
April 15 remains the anchor date of the U.S. tax system. Both individuals and C corporations must file 2025 income tax returns or extension requests. Many taxpayers must also make their first estimated payment for 2026.
Forms to file:
Action: File your 2025 returns or extensions, pay any remaining tax due, and make your Q1 2026 estimated payment.
💡 Key point: Even with an extension, interest begins accruing on unpaid balances starting April 15.
Employers must report payroll taxes withheld during the first quarter of 2026.
Forms to file:
Action: File Form 941 for January to March wages and reconcile payroll deposits.
💡 Key point: Accurate Q1 filings help maintain compliance and prevent trust-fund penalties.
Midway through the year, corporations and individuals must make their second estimated payment for 2026.
Forms to file:
Action: Submit your Q2 payment through EFTPS and adjust for updated income or deductions.
💡 Key point: Adjusting estimates throughout the year avoids large tax bills, or overpayments, in April.
Employers must submit their second-quarter federal payroll return.
Forms to file:
Action: Submit your return, verify all payroll deposits and confirm accuracy mid-year.
💡 Key point: Consistent reconciliation minimizes year-end corrections.
This major compliance date includes the final filing of extended pass-through returns and the third quarterly estimated tax payment for 2026.
Forms to file:
Action: File all extended entity returns, issue remaining K-1s and submit your Q3 estimated payment.
💡 Key point: September is a critical month. Business and personal obligations overlap, making organization essential.
For taxpayers who filed extensions in April, this is the final deadline to submit 2025 returns.
Forms to file:
Action: File extended 2025 returns by this date. No additional extensions are available.
💡 Key point: This is the last chance to finalize 2025 filings before late-filing penalties apply.
The third-quarter payroll filing covers July through September wage reporting.
Forms to file:
Action: Submit your return and verify withholdings before year-end processing begins.
💡 Key point: Clean Q3 reporting reduces audit risk and eliminates fourth-quarter scrambling.
For holidays, closures and the remaining dates of the year, see our key U.S. business dates for the second half of 2026.
Not always. While federal deadlines form the foundation, every state sets its own rules. For example:
Building a unified tax calendar that combines federal, state and local obligations keeps compliance predictable and transparent, no matter where your business scales next. Learn how Orbiss can help with U.S. corporate tax and payroll, or contact us.
Calendar-year C corporations must file Form 1120, or request an extension with Form 7004, by April 15, 2026. The extended deadline is October 15, 2026, and no additional extensions are available. Interest begins accruing on unpaid balances starting April 15, even with an extension.
Calendar-year partnerships (Form 1065) and S corporations (Form 1120-S) must file by March 16, 2026, or submit an extension to September 15, 2026. Schedule K-1s go to each partner or shareholder.
Form 941 is filed quarterly: April 30, 2026 for Q1, July 31, 2026 for Q2 and October 31, 2026 for Q3.
January 31, 2026 for 2025 wages and contractor payments, along with Form 940, the annual federal unemployment (FUTA) tax return.
The Q4 2025 payment is due January 15, 2026. For 2026, the Q1 payment is due April 15, the Q2 payment June 15 and the Q3 payment September 15, 2026.
This article is for general informational purposes only and does not constitute legal, tax, or accounting advice. Rules and requirements vary by company, individual, and jurisdiction, and can change. Please seek advice appropriate to your specific situation.