When Are Business Taxes Due? Deadlines, Extensions, and Estimated Payments

Federal business tax deadlines depend on how your business is structured and what tax year it uses. For calendar-year filers, partnerships and S corporations file by March 15, sole proprietors and C corporations file by April 15, and every business with employees or contractors has additional payroll and information-return dates spread across the year. In 2026, March 15 falls on a Sunday, so the pass-through deadline shifts to Monday, March 16.¹

Deadlines by Entity Type for Calendar-Year Filers

Partnerships and Multi-Member LLCs

Partnerships and multi-member LLCs taxed as partnerships file Form 1065 by the 15th day of the third month after the tax year ends. For a calendar year, that’s March 15 (March 16 in 2026).¹ The early date exists so that each partner receives a Schedule K-1 in time to report their share of income on their personal Form 1040.²

Late filing is costly. The IRS charges $255 per month or partial month for each partner listed on the return, for up to 12 months.³

S Corporations

S corporations file Form 1120-S on the same March 15 deadline as partnerships.⁴ The same $255-per-shareholder monthly penalty applies for late filing.³

Sole Proprietors and Single-Member LLCs

If you run a sole proprietorship or a single-member LLC, you report business income on Schedule C attached to your personal Form 1040. Your deadline is April 15.⁵ In 2026, April 15 is a Wednesday with no holiday conflicts, so no adjustment applies.

C Corporations

C corporations file Form 1120 by the 15th day of the fourth month after the tax year ends. For calendar-year corporations, that’s April 15.²

Filing Form 1120 or Form 1040 late triggers a failure-to-file penalty of 5% of unpaid tax for each month the return is overdue, capped at 25%. Because the penalty is based on unpaid tax, filing on time when you owe nothing costs you nothing.³

When the Date Falls on a Weekend or Holiday

Any federal filing deadline landing on a Saturday, Sunday, or legal holiday moves to the next business day. Emancipation Day, observed in Washington, D.C. on April 16, can push the April 15 individual and corporate deadline forward in some years.⁶

Fiscal-Year Filers

If your business uses a tax year that ends on a date other than December 31, count forward from your year-end rather than the calendar.²

Partnerships and S corporations: 15th day of the third month after the fiscal year ends.
C corporations: 15th day of the fourth month after the fiscal year ends.
C corporations with a June 30 year-end use a special rule and file by the 15th day of the third month (September 15).⁵

A partnership with a June 30 year-end files Form 1065 by September 15. A C corporation ending its year on March 31 files by July 15.

Quarterly Estimated Tax Payments

Federal income tax is pay-as-you-go, so most businesses owe estimated tax throughout the year. Sole proprietors, partners, and S corporation shareholders use Form 1040-ES to figure their payments.⁷ C corporations that expect to owe $500 or more compute their own estimates using the worksheet in the Form 1120 instructions; Form 1120-W was discontinued after 2022.⁸

For calendar-year taxpayers, the four installments fall on:⁹

First quarter (January–March): April 15
Second quarter (April–May): June 15
Third quarter (June–August): September 15
Fourth quarter (September–December): January 15 of the following year

You can avoid the underpayment penalty by paying at least 90% of the current year’s tax or 100% of the tax shown on the prior year’s return, whichever is smaller.¹⁰ If your prior-year adjusted gross income was over $150,000 ($75,000 if married filing separately), the 100% threshold rises to 110%.¹¹

Payroll and Information Returns

If your business has employees or pays independent contractors, several other returns are due regardless of your entity type.

Form 941 (Quarterly Payroll Taxes)

Employers withholding income tax and Social Security/Medicare from wages file Form 941 quarterly:¹²

First quarter: April 30
Second quarter: July 31
Third quarter: October 31
Fourth quarter: January 31 of the following year

If you deposited all payroll taxes on time and in full for the quarter, you get an additional 10 days to file.¹²

Form 940 (Annual Federal Unemployment Tax)

Form 940 is filed once per year, due January 31 for calendar-year employers. Depositing all FUTA tax on time extends the filing date to February 10.²

Forms 1099 for Contractors and Other Payments

If your business paid $600 or more to a contractor or other nonemployee during the year, you must file an information return:

Form 1099-NEC (nonemployee compensation): January 31, whether paper or electronic.¹³
Form 1099-MISC (rents, royalties, other payments): February 28 on paper, March 31 electronically.¹³

Businesses filing 10 or more information returns of any kind (including W-2s) must file them electronically.¹⁴ For 1099s due in 2026, late-filing penalties run $60 per form if corrected within 30 days, $130 if corrected by August 1, and $340 after that or if not filed at all. Intentional disregard raises the penalty to $680 per return.¹⁵

Extensions: More Time to File, Not to Pay

If you cannot finish your return by the original deadline, you can get an automatic extension. What you cannot extend is the payment.

Partnerships, S corporations, and C corporations file Form 7004 by the original due date for an automatic six-month extension.¹⁶ C corporations with a June 30 fiscal year-end receive seven months instead of six.¹⁷ Sole proprietors and single-member LLCs use Form 4868 to extend their personal return, moving the deadline from April 15 to October 15.¹⁸

For 2026 calendar-year filers, extended deadlines land on:

Partnerships and S corporations: September 15
C corporations and sole proprietors: October 15

Tax you owe is still due on the original deadline. If you file by the extended date but pay late, the IRS charges a failure-to-pay penalty of 0.5% of the unpaid balance per month, up to 25%, and interest accrues from the original due date. Filing your individual return on time and setting up an approved IRS payment plan reduces the failure-to-pay rate to 0.25% per month.¹⁹

Key 2026 Deadlines at a Glance

For calendar-year businesses, the year’s most common federal deadlines are:

January 15: Fourth quarter estimated tax (prior year)
January 31: Form 1099-NEC; Form 940 (FUTA); Form 941 for the fourth quarter
February 28: Form 1099-MISC (paper)
March 16: Forms 1065 and 1120-S (March 15 falls on Sunday)
March 31: Form 1099-MISC (electronic)
April 15: Form 1040 with Schedule C; Form 1120; first quarter estimated tax
April 30: Form 941 for the first quarter
June 15: Second quarter estimated tax
July 31: Form 941 for the second quarter
September 15: Third quarter estimated tax; extended deadline for Forms 1065 and 1120-S
October 15: Extended deadline for Form 1040 and Form 1120
October 31: Form 941 for the third quarter

Fiscal-year businesses should substitute their own year-end date and count forward by the number of months that applies to their entity type. Any deadline falling on a weekend or federal holiday moves to the next business day.

1
Internal Revenue Service. Instructions for Form 1065 (2025)
2
Internal Revenue Service. Publication 509 (2026), Tax Calendars
3
Internal Revenue Service. Failure to File Penalty
4
Internal Revenue Service. About Form 1120-S, U.S. Income Tax Return for an S Corporation
5
Internal Revenue Service. Starting or Ending a Business
6
Internal Revenue Service. When to File
7
Internal Revenue Service. About Form 1040-ES, Estimated Tax for Individuals
8
Internal Revenue Service. Estimated Taxes
9
Internal Revenue Service. Estimated Tax
10
Office of the Law Revision Counsel. 26 USC 6654 – Failure by Individual to Pay Estimated Income Tax
11
Internal Revenue Service. Underpayment of Estimated Tax by Individuals Penalty
12
Internal Revenue Service. Instructions for Form 941
13
Internal Revenue Service. Instructions for Forms 1099-MISC and 1099-NEC
14
Internal Revenue Service. Topic No. 801, Who Must File Information Returns Electronically
15
Internal Revenue Service. Information Return Penalties
16
Internal Revenue Service. About Form 7004, Application for Automatic Extension of Time to File Certain Business Income Tax, Information, and Other Returns
17
Internal Revenue Service. 3.11.212 Applications for Extension of Time to File
18
Internal Revenue Service. Form 4868, Application for Automatic Extension of Time to File U.S. Individual Income Tax Return
19
Internal Revenue Service. Failure to Pay Penalty