Key Tax Deadlines & Filing Calendar

Missing a tax deadline can result in costly penalties and interest. This guide highlights the most important federal tax due dates for small businesses, including quarterly estimated tax payments, annual return deadlines by business structure, and W-2/1099 filing requirements.

Quarterly Estimated Tax Deadlines

If you expect to owe $1,000 or more in taxes for the year (after subtracting withholding and credits), you may need to make quarterly estimated tax payments. This is especially common for self-employed individuals, partners, S-corp shareholders, and corporations.

For the 2025 tax year, the federal quarterly estimated tax deadlines are:

  • 1st Quarter: April 15, 2025

  • 2nd Quarter: June 16, 2025 (since June 15 is a Sunday)

  • 3rd Quarter: September 15, 2025

  • 4th Quarter: January 15, 2026

If a deadline falls on a weekend or legal holiday, it moves to the next business day. Corporations must pay electronically via the Electronic Federal Tax Payment System (EFTPS). Many states follow the same or similar schedules, but always check your state’s requirements.

Annual Tax Return Deadlines by Business Structure

  • Sole Proprietorships: April 15 (Form 1040 with Schedule C)

  • Single-Member LLCs: April 15 (same as sole proprietorship)

  • Partnerships: March 15 (Form 1065)

  • Multi-Member LLCs: March 15 (default partnership treatment)

  • S Corporations: March 15 (Form 1120S)

  • C Corporations: April 15 (Form 1120, for calendar-year filers)

If your business uses a fiscal year, the deadline is the 15th day of the third month (partnerships, S-corps) or fourth month (C-corps) after the close of your fiscal year. If a deadline falls on a weekend or holiday, it moves to the next business day. Extensions are available if requested by the original due date.

W-2 and 1099 Due Dates

  • Form W-2: Provide to employees and file with the Social Security Administration by January 31.

  • Form 1099-NEC: Provide to nonemployees (e.g., independent contractors) and file with the IRS by January 31.

  • Other 1099 Forms: Generally provide to recipients by January 31. File with the IRS by February 28 (paper) or March 31 (electronic), with some exceptions for certain forms.

If a due date falls on a weekend or legal holiday, the deadline is the next business day.

Downloadable and Syncable Calendars

To help you stay organized:

  • Download a printable PDF tax calendar from the IRS website or your accounting software provider.

  • Many online tax calendars (including the IRS Tax Calendar for Businesses and Self-Employed) offer the option to sync deadlines with your Google Calendar or other digital calendar apps.

Conclusion

Staying on top of tax deadlines is crucial for avoiding penalties and interest. Mark these dates on your calendar, set reminders, and consider syncing with a digital calendar for extra peace of mind.

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