When Are Business Taxes Due? Deadlines by Entity

Fact-checked by the LegalGlass editorial team against primary sources · Published Aug 6, 2026 · Last updated Aug 6, 2026

Business tax deadlines depend on your entity. Partnerships and S corporations file by the 15th day of the third month after the tax year ends - March 15 for calendar-year filers. Sole proprietors filing Schedule C and C corporations file by the 15th day of the fourth month - April 15 for calendar-year filers - under 26 U.S. Code § 6072. Extensions move the filing date, not the payment date.

Business Tax Deadlines at a Glance

Federal income tax return deadlines are set by 26 U.S. Code § 6072, which fixes the month by entity type rather than a single calendar date. Pass-through entities that issue Schedule K-1s file in the third month so their owners have the figures before individual returns are due; individuals and C corporations file in the fourth month. The dates below assume a calendar (January–December) tax year; a fiscal-year filer counts the same third or fourth month from its own year-end.

When a listed date lands on a Saturday, Sunday, or legal holiday, the deadline moves to the next business day. Always confirm the exact date for the current filing season on the IRS tax calendar. The pattern is easy to remember: the pass-through returns that generate K-1s (Form 1065 and Form 1120-S) are due one month before the returns that receive them (Form 1040 and Form 1120). An extension adds six months to each, landing partnerships and S corporations on September 15 and individuals and C corporations on October 15 for a calendar-year filer.

Sole Proprietors and Single-Member LLCs

A sole proprietor or single-member LLC reports business income on Schedule C as part of Form 1040, so the business deadline is the individual return deadline: the 15th day of the fourth month after the tax year, or April 15 for a calendar-year filer, under § 6072(a). There is no separate business filing date because the entity is disregarded.

These owners also owe self-employment tax on Schedule SE, which is filed with the same 1040, and they typically make quarterly estimated payments during the year. An extension to October 15 is available on Form 4868 but does not extend time to pay.

Partnerships and Multi-Member LLCs

A partnership or multi-member LLC files Form 1065 by the 15th day of the third month after the end of its tax year - March 15 for a calendar-year partnership - under § 6072(b). The earlier deadline exists because the partnership must issue a Schedule K-1 to each partner so they can report their share on their own returns.

Form 1065 is an information return, but filing late still triggers a penalty charged per partner for each month late, even when no tax is due. A partnership extends to September 15 with Form 7004. Partners themselves generally pay estimated tax on their pass-through income during the year.

S Corporations

An S corporation files Form 1120-S by the 15th day of the third month after its tax year ends - March 15 for a calendar-year S corporation - the same third-month rule in § 6072(b) that applies to partnerships. It issues a Schedule K-1 to each shareholder, who reports the income on a personal return.

Like a partnership, an S corporation that files late owes a per-shareholder penalty for each month the return is late. It extends to September 15 with Form 7004. Owner-employees also have payroll tax deadlines during the year, separate from the annual return. If you are still deciding on the election, see Form 2553 explained.

C Corporations

A C corporation files Form 1120 by the 15th day of the fourth month after the end of its tax year - April 15 for a calendar-year corporation - under § 6072(a). Unlike the pass-throughs, a C corporation pays its own income tax with the return, so the filing and payment fall together at the original deadline.

A C corporation extends to October 15 with Form 7004 and generally must pay estimated tax in four installments through EFTPS if it expects to owe $500 or more. A fiscal-year C corporation counts the fourth month from its own year-end. A historical exception applies to corporations with a June 30 fiscal year-end, which have a different deadline.

Quarterly Estimated Tax Dates

Beyond the annual return, most business owners owe estimated tax during the year because no employer withholds on business income. Per the IRS, the four calendar-year payment dates are April 15, June 15, September 15, and January 15 of the following year. Individuals generally must pay if they expect to owe $1,000 or more; corporations if they expect to owe $500 or more.

These dates do not line up evenly with the quarters - the second covers two months and the third covers three - but equal payments on each date keep you current. See how to pay quarterly estimated taxes for the safe-harbor rules that avoid a penalty.

Extensions and the Weekend Rule

An extension buys time to file, never time to pay. Corporations and partnerships file Form 7004 for an automatic six-month extension; sole proprietors file Form 4868 to extend Form 1040. In both cases the tax owed is still due at the original deadline, so pay an estimate by then to limit the failure-to-pay penalty and interest.

When any deadline falls on a Saturday, Sunday, or legal holiday, it moves to the next business day - which is why the "April 15" and "March 15" dates shift by a day or two in some years. Because the exact date can move, confirm the current-season date on the IRS tax calendar before you rely on it.

Penalties for Missing a Deadline

Missing a filing or payment deadline triggers penalties under 26 U.S. Code § 6651. The IRS failure-to-file penalty is 5% of the unpaid tax per month up to 25%, and the failure-to-pay penalty is 0.5% per month up to 25%, with interest on top. Partnerships and S corporations face an additional per-owner late-filing penalty because their returns are information returns.

Underpaying estimated tax carries its own penalty under § 6654 for individuals. Filing on time, even without full payment, avoids the larger failure-to-file penalty - so file or extend by the deadline no matter what. For the full filing walkthrough, see how to file business taxes.

Employment and Information-Return Deadlines

If your business has employees or pays contractors, the income tax return is only part of the calendar. Per the IRS, employers file Form 941 quarterly to report withheld income tax and Social Security and Medicare taxes, and Form 940 annually for federal unemployment (FUTA) tax. Payroll tax deposits follow a monthly or semiweekly schedule set by the size of the employer's liability, separate from these return dates.

Information returns have an early, fixed deadline. Employers must furnish Form W-2 to employees and file it with the Social Security Administration, and businesses must issue Form 1099-NEC to contractors, by January 31 following the tax year. Missing the January 31 date carries its own penalty per form. These deadlines fall before the entity income tax returns, so a business with a payroll runs several filing dates across the first quarter.

Fiscal-Year Filers

The March 15 and April 15 dates apply to calendar-year businesses; a fiscal-year filer counts the same third or fourth month from its own year-end under 26 U.S. Code § 6072. A partnership or S corporation with a June 30 year-end, for example, files by September 15 - the 15th day of the third month after June 30 - and a C corporation with that year-end files by October 15. Adopting or changing a fiscal year has its own IRS rules, so most small businesses simply use the calendar year and the standard dates above. When in doubt, confirm your entity's exact date on the IRS tax calendar.

Related Guides

• Form 1120 vs. 1120-S vs. 1065 - which return each entity files.
• Schedule C - the sole-proprietor return due April 15.
• How to file business taxes - the step-by-step by entity.
• Quarterly estimated taxes - the four in-year deadlines.
• Self-employment tax - filed with the annual 1040.
• Form 2553 explained - the S-corp deadline and election.
• Single-member LLC - why it uses the April 15 date.
• S-corp vs. LLC - how structure changes your deadlines.
• LLC vs. S-corp tax - the tax trade-offs behind the choice.
• Business tax hub - all returns, schedules, and deadlines.

Frequently Asked Questions

When are business taxes due?

Partnerships and S corporations file by the 15th day of the third month after the tax year ends - March 15 for calendar-year filers. Sole proprietors and C corporations file by the 15th day of the fourth month - April 15 for calendar-year filers - under 26 U.S. Code § 6072.

When is a partnership tax return due?

A partnership files Form 1065 by the 15th day of the third month after the end of its tax year, which is March 15 for a calendar-year partnership. If that date is a weekend or legal holiday, the deadline moves to the next business day.

When is an S corporation return due?

An S corporation files Form 1120-S by the 15th day of the third month after its tax year ends - March 15 for calendar-year filers. An extension on Form 7004 moves the filing deadline to September 15 for a calendar-year S corporation.

Does a tax extension give me more time to pay?

No. Form 7004 for entities and Form 4868 for individuals extend only the time to file, not the time to pay. Any tax owed is still due at the original deadline, and the failure-to-pay penalty and interest run from that date.

What are the quarterly estimated tax due dates?

For a calendar-year taxpayer, estimated tax payments are due April 15, June 15, September 15, and January 15 of the following year, per the IRS. If a due date falls on a weekend or legal holiday, the payment is due the next business day.

What happens if I file my business taxes late?

The IRS charges a failure-to-file penalty of 5% of unpaid tax per month up to 25% and a failure-to-pay penalty of 0.5% per month up to 25%, under 26 U.S. Code § 6651. Partnerships and S corporations also owe a per-owner late-filing penalty.

Sources

1. Cornell LII - 26 U.S. Code § 6072, Time for filing income tax returns (3rd-month and 4th-month deadlines by entity).
2. IRS - About Form 1065, U.S. Return of Partnership Income.
3. IRS - About Form 1120-S, U.S. Income Tax Return for an S Corporation.
4. IRS - About Form 1120, U.S. Corporation Income Tax Return.
5. IRS - About Schedule C (Form 1040) (filed with Form 1040).
6. IRS - Estimated Taxes (April 15, June 15, September 15, January 15; $1,000 / $500 thresholds).
7. IRS - About Form 7004 (automatic 6-month extension for business returns).
8. IRS - About Form 4868 (individual extension for Form 1040).
9. IRS - Online Tax Calendar (current-season dates; weekend/holiday rule).
10. IRS - Employment Taxes (Form 941 quarterly, Form 940 annual).
11. IRS - About Form 1099-NEC (January 31 deadline for contractor pay).
12. IRS - Failure to File Penalty (5% per month, up to 25%).
13. Cornell LII - 26 U.S. Code § 6651, Failure to file tax return or to pay tax.
14. Cornell LII - 26 U.S. Code § 6654, Failure by individual to pay estimated income tax.

LegalGlass provides general information for educational purposes and is not a law firm or a substitute for advice from a licensed attorney or tax professional. This page is information, not advice. Filing dates shift for weekends and holidays and change year to year; verify the current-season deadlines with the IRS before acting.