Your guide to 2025–2026 U.S. business tax deadlines, forms, and filings.
Expanding into the U.S. means navigating a multi-layered tax landscape unlike any other. For international founders, the challenge isn’t just compliance - it’s tracking specific obligations across federal, state, and local jurisdictions.
To help you stay organized and penalty-free, here is a detailed breakdown of the major U.S. business tax deadlines for the 2025 - 2026 cycle.
Q4 2025 Estimated Tax Payment - January 15, 2026
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.
Year-End Employer Filings (2025) - January 31, 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, issue W-2s and 1099-NECs.
💡 Key point: Timely, accurate reporting ensures
a smooth transition into the 2026 payroll cycle.
Partnership & S-Corporation Returns (2025) - March 16, 2026
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.
Individual & C-Corporation Returns + Q1 2026 Estimated Taxes - April 15, 2026
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.
Q1 2026 Payroll Filings - April 30, 2026
Employers must report payroll taxes withheld during the first quarter of 2026.
Forms to file:
Action:
File Form 941 for January - March wages and reconcile payroll deposits.
💡 Key point: Accurate Q1 filings help maintain compliance
and prevent trust-fund penalties.
Q2 2026 Estimated Tax Payment - June 15, 2026
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.
Q2 2026 Payroll Filings - July 31, 2026
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.
Extended Partnership & S-Corp Returns + Q3 Estimated Taxes - September 15, 2026
This major compliance date includes 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.
Q3 2026 Payroll Filings - October 31, 2026
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.
Extended Individual & C-Corporation Returns - October 15, 2026
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.
Final Note: Stay Aligned on State Deadlines
While federal deadlines form the foundation, every state sets its own rules.
Building a unified tax calendar that combines federal, state, and local obligations keeps compliance predictable and transparent, no matter where your business scales next.