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Business tax deadlines for 2026 and 2027: S corporation and partnership returns are due March 16, 2026 and March 15, 2027, and C corporation returns April 15, with Form 7004 extensions to September 15 and October 15. Corporate estimated tax is due April 15, June 15, September 15 and December 15. 2027 dates are computed until the IRS publishes them.
This is general information, not tax advice for your situation. Tax services are provided by licensed tax professionals under a separate engagement agreement. BEG does not provide tax advice.
This IRS tax calendar for businesses covers federal income tax dates: returns and extensions, estimated tax, S corporation and entity elections, the January information returns, and the research credit dates that ride on them. Dates in 2026 come from IRS Publication 509 (2026) unless marked computed. Dates in 2027 and January 2028 are computed from the rules; IRS Publication 509 (2027) has not been released, so recheck them when it is. Payroll deposit and Form 941 filing dates are on the separate payroll tax calendar.
Showing 52 of 52 dates.
Fourth Form 1040-ES installment for 2025, for sole proprietors and for S corporation shareholders and partners who pay estimated tax. Filing the 2025 Form 1040 and paying in full by February 2, 2026 takes the place of this payment.
Date source: IRS Publication 509 (2026)
Give employees their 2025 Forms W-2 and file Copy A with Form W-3. File Form 1099-NEC for 2025 nonemployee compensation and give each recipient a copy. January 31 fell on a Saturday.
Date source: IRS Publication 509 (2026)
If you elected the research payroll tax credit, attach Form 8974 to this Form 941 to take the credit against the employer share of Social Security tax, then Medicare tax. Deposit and filing rules for Form 941 itself are on the payroll tax calendar.
Date source: IRS Publication 509 (2026)
File the return and give each shareholder or partner a Schedule K-1, or file Form 7004 by today for an automatic 6-month extension to September 15. Form 7004 extends the time to file, not to pay. March 15 fell on a Sunday. A qualified small business makes the research payroll tax credit election on Form 6765 attached to this return, filed on time.
Date source: IRS Publication 509 (2026)
A corporation, or an LLC eligible to be taxed as one, files Form 2553 no more than 2 months and 15 days after the start of the tax year the election is to take effect. Filed late, S status starts in 2027 unless late-election relief applies (generally within 3 years and 75 days).
Date source: IRS Publication 509 (2026)
An eligible entity such as an LLC chooses how it is taxed on Form 8832. The election can take effect up to 75 days before the filing date and no more than 12 months after it, so March 17 is the last filing day for a January 1 start. After a change, another change generally waits 60 months.
Date source: Computed from the Form 8832 instructions (75-day rule)
File and pay any tax due, or file Form 7004 by today for an automatic 6-month extension to October 15 and deposit the tax you expect to owe. A qualified small business makes the research payroll tax credit election on Form 6765 attached to this return, filed on time.
Date source: IRS Publication 509 (2026)
Sole proprietors report business income on Schedule C. S corporation shareholders and partners report their Schedule K-1 amounts on their own return. Form 4868 by today gives an automatic 6-month extension to October 15; pay what you expect to owe today.
Date source: IRS Publication 509 (2026)
Calendar-year C corporations pay estimated tax on the 15th day of the 4th, 6th, 9th and 12th months of the tax year.
Date source: IRS Publication 509 (2026)
First Form 1040-ES installment for sole proprietors and business owners who do not cover their tax through withholding.
Date source: IRS Publication 509 (2026)
If you elected the research payroll tax credit, attach Form 8974 to this Form 941 to take the credit against the employer share of Social Security tax, then Medicare tax. Deposit and filing rules for Form 941 itself are on the payroll tax calendar.
Date source: IRS Publication 509 (2026)
Second installment for calendar-year C corporations.
Date source: IRS Publication 509 (2026)
Second Form 1040-ES installment for 2026.
Date source: IRS Publication 509 (2026)
If you elected the research payroll tax credit, attach Form 8974 to this Form 941 to take the credit against the employer share of Social Security tax, then Medicare tax. Deposit and filing rules for Form 941 itself are on the payroll tax calendar.
Date source: IRS Publication 509 (2026)
Due only if Form 7004 was filed by March 16. Give owners their final Schedules K-1 with the return.
Date source: IRS Publication 509 (2026)
The qualified small business payroll election is made on Form 6765 with a timely filed original return, including extensions, and cannot be made on an amended return. For an extended 2025 Form 1120-S or Form 1065, this is the last day.
Date source: IRS Publication 509 (2026)
Third installment for calendar-year C corporations.
Date source: IRS Publication 509 (2026)
Third Form 1040-ES installment for 2026.
Date source: IRS Publication 509 (2026)
Due only if Form 7004 was filed by April 15.
Date source: IRS Publication 509 (2026)
Due only if Form 4868 was filed by April 15.
Date source: IRS Publication 509 (2026)
Same rule for C corporations and for sole proprietors that qualify: the election rides on the timely filed original return, including extensions, and cannot be added by amendment.
Date source: IRS Publication 509 (2026)
A refund claim, such as an amended return adding a missed research credit, is due within 3 years from the date the return was filed, or 2 years from when the tax was paid if later. A calendar-year 2022 Form 1120 or Form 1040 filed on its October 16, 2023 extended due date reaches 3 years today. A return filed on another date has its own anniversary.
Date source: Computed from IRC 6511(a); filing date per IRS Publication 509 (2023)
If you elected the research payroll tax credit, attach Form 8974 to this Form 941 to take the credit against the employer share of Social Security tax, then Medicare tax. Deposit and filing rules for Form 941 itself are on the payroll tax calendar. IRS example: a calendar-year 2025 return that made the election and was filed April 15, 2026 first takes the credit on this return. October 31 falls on a Saturday.
Date source: IRS Publication 509 (2026)
Last 2026 installment for calendar-year C corporations.
Date source: IRS Publication 509 (2026)
Fourth Form 1040-ES installment for 2026. Filing the 2026 Form 1040 and paying in full by February 1, 2027 takes the place of this payment.
Date source: Computed from the rules; IRS Publication 509 (2027) not yet released
Give employees their 2026 Forms W-2 and file Copy A with Form W-3. File Form 1099-NEC for 2026 nonemployee compensation and give each recipient a copy. January 31, 2027 falls on a Sunday.
Date source: Computed from the rules; IRS Publication 509 (2027) not yet released
If you elected the research payroll tax credit, attach Form 8974 to this Form 941 to take the credit against the employer share of Social Security tax, then Medicare tax. Deposit and filing rules for Form 941 itself are on the payroll tax calendar.
Date source: Computed from the rules; IRS Publication 509 (2027) not yet released
File the return and give each shareholder or partner a Schedule K-1, or file Form 7004 by today for an automatic 6-month extension to September 15, 2027. A qualified small business makes the research payroll tax credit election on Form 6765 attached to this return, filed on time.
Date source: Computed from the rules; IRS Publication 509 (2027) not yet released
No more than 2 months and 15 days after the start of the 2027 tax year. Filed late, S status starts in 2028 unless late-election relief applies.
Date source: Computed from the rules; IRS Publication 509 (2027) not yet released
Form 8832 can take effect up to 75 days before the filing date, so March 17 is the last filing day for a January 1 start. The earliest filing day for that start is January 1, 2026, 12 months ahead.
Date source: Computed from the Form 8832 instructions (75-day rule); IRS Publication 509 (2027) not yet released
File and pay any tax due, or file Form 7004 by today for an automatic 6-month extension to October 15, 2027. A qualified small business makes the research payroll tax credit election on Form 6765 attached to this return, filed on time.
Date source: Computed from the rules; IRS Publication 509 (2027) not yet released
Form 4868 by today gives an automatic 6-month extension to October 15, 2027. District of Columbia Emancipation Day (April 16) falls on a Friday in 2027, so it does not move this date.
Date source: Computed from the rules; IRS Publication 509 (2027) not yet released
First installment for calendar-year C corporations.
Date source: Computed from the rules; IRS Publication 509 (2027) not yet released
First Form 1040-ES installment for 2027.
Date source: Computed from the rules; IRS Publication 509 (2027) not yet released
A calendar-year 2023 Form 1120 filed on or before its April 15, 2024 due date counts as filed on that date, so the 3-year window for an amended return adding a missed research credit closes today. Form 1120 filers must use a formal amended return.
Date source: Computed from IRC 6511(a) and 6513(a); due date per IRS Publication 509 (2024)
If you elected the research payroll tax credit, attach Form 8974 to this Form 941 to take the credit against the employer share of Social Security tax, then Medicare tax. Deposit and filing rules for Form 941 itself are on the payroll tax calendar.
Date source: Computed from the rules; IRS Publication 509 (2027) not yet released
Second installment for calendar-year C corporations.
Date source: Computed from the rules; IRS Publication 509 (2027) not yet released
Second Form 1040-ES installment for 2027.
Date source: Computed from the rules; IRS Publication 509 (2027) not yet released
If you elected the research payroll tax credit, attach Form 8974 to this Form 941 to take the credit against the employer share of Social Security tax, then Medicare tax. Deposit and filing rules for Form 941 itself are on the payroll tax calendar. July 31, 2027 falls on a Saturday.
Date source: Computed from the rules; IRS Publication 509 (2027) not yet released
Due only if Form 7004 was filed by March 15, 2027.
Date source: Computed from the rules; IRS Publication 509 (2027) not yet released
The election rides on the timely filed original return, including extensions. It cannot be made on an amended return.
Date source: Computed from the rules; IRS Publication 509 (2027) not yet released
Third installment for calendar-year C corporations.
Date source: Computed from the rules; IRS Publication 509 (2027) not yet released
Third Form 1040-ES installment for 2027.
Date source: Computed from the rules; IRS Publication 509 (2027) not yet released
Due only if Form 7004 was filed by April 15, 2027.
Date source: Computed from the rules; IRS Publication 509 (2027) not yet released
Due only if Form 4868 was filed by April 15, 2027.
Date source: Computed from the rules; IRS Publication 509 (2027) not yet released
The election rides on the timely filed original return, including extensions. It cannot be made on an amended return.
Date source: Computed from the rules; IRS Publication 509 (2027) not yet released
A calendar-year 2023 Form 1120 or Form 1040 filed on its October 15, 2024 extended due date reaches 3 years today, the usual limit for an amended return claiming a missed research credit.
Date source: Computed from IRC 6511(a); filing date per IRS Publication 509 (2024)
If you elected the research payroll tax credit, attach Form 8974 to this Form 941 to take the credit against the employer share of Social Security tax, then Medicare tax. Deposit and filing rules for Form 941 itself are on the payroll tax calendar. October 31, 2027 falls on a Sunday.
Date source: Computed from the rules; IRS Publication 509 (2027) not yet released
Last 2027 installment for calendar-year C corporations.
Date source: Computed from the rules; IRS Publication 509 (2027) not yet released
Fourth Form 1040-ES installment for 2027. January 15, 2028 is a Saturday and Monday, January 17 is Martin Luther King Jr. Day, so the date moves to Tuesday.
Date source: Computed from the rules; IRS Publication 509 (2027) not yet released
Give employees their 2027 Forms W-2 and file Copy A with Form W-3. File Form 1099-NEC for 2027 nonemployee compensation and give each recipient a copy.
Date source: Computed from the rules; IRS Publication 509 (2027) not yet released
If you elected the research payroll tax credit, attach Form 8974 to this Form 941 to take the credit against the employer share of Social Security tax, then Medicare tax. Deposit and filing rules for Form 941 itself are on the payroll tax calendar.
Date source: Computed from the rules; IRS Publication 509 (2027) not yet released
Each date on the calendar comes from a rule that counts from the end of the tax year. For a calendar-year business the rules produce the dates below. Checked September 25, 2026.
| Return | Who | Rule | 2026 | 2027 (computed) |
|---|---|---|---|---|
| Form 1120 | C corporations | 15th day of the 4th month after the tax year ends | April 15, 2026 | April 15, 2027 |
| Form 1120-S | S corporations | 15th day of the 3rd month | March 16, 2026 | March 15, 2027 |
| Form 1065 | Partnerships, including multi-member LLCs by default | 15th day of the 3rd month | March 16, 2026 | March 15, 2027 |
| Form 1040 | Sole proprietors (Schedule C) and owners reporting Schedules K-1 | 15th day of the 4th month | April 15, 2026 | April 15, 2027 |
| Form 7004 | Corporations and partnerships | Automatic 6-month extension to file, filed by the original due date | September 15 (1120-S, 1065) and October 15 (1120), 2026 | September 15 and October 15, 2027 |
| Form 4868 | Individuals, including sole proprietors | Automatic 6-month extension to file | October 15, 2026 | October 15, 2027 |
| Payment or filing | Who | Rule | 2026 | 2027 (computed) |
|---|---|---|---|---|
| Corporate estimated tax | C corporations | 15th day of the 4th, 6th, 9th and 12th months | April 15, June 15, September 15, December 15 | April 15, June 15, September 15, December 15 |
| Individual estimated tax (Form 1040-ES) | Sole proprietors and pass-through owners | April 15, June 15, September 15, then January 15 | April 15, June 15, September 15; January 15, 2027 | April 15, June 15, September 15; January 18, 2028 |
| Form 2553, S election | Corporations and LLCs eligible to be taxed as one | No more than 2 months and 15 days into the tax year | March 16, 2026 (for 2026) | March 15, 2027 (for 2027) |
| Form 8832, entity classification | LLCs and other eligible entities | Effective up to 75 days before filing, and no more than 12 months after | March 17, 2026 (for January 1, 2026) | March 17, 2027 (for January 1, 2027) |
| Forms W-2, W-3 and 1099-NEC | Employers and payers | January 31 | February 2, 2026 (2025 forms) | February 1, 2027 (2026 forms) |
When a due date lands on a Saturday, Sunday or legal holiday, IRC 7503 makes the next business day timely. That rule explains the odd dates: March 16, 2026 for S corporations and partnerships (March 15 was a Sunday), November 2, 2026 for the third-quarter Form 941 (October 31 is a Saturday), and Tuesday, January 18, 2028 for the last 2027 individual estimate (January 15 is a Saturday and Monday the 17th is Martin Luther King Jr. Day). District of Columbia Emancipation Day, April 16, falls on a Thursday in 2026 and a Friday in 2027, so April 15 holds both years. A statewide legal holiday delays a filing date only where the IRS office you file with is in that state or, for individuals, in your home state, and it never delays a federal tax deposit.
Fiscal-year businesses count from their own year end: Forms 1120-S and 1065 on the 15th day of the 3rd month, Form 1120 on the 15th day of the 4th month, corporate estimates in the 4th, 6th, 9th and 12th months, and individual estimates in the 4th, 6th and 9th months and the 1st month after the year ends. A C corporation with a June 30 year that began before 2026 files by the 15th day of the 3rd month and gets a 7-month extension with Form 7004.
The R&D payroll tax credit election has no date of its own. A qualified small business, one with under $5 million of gross receipts for the year and none before the last five years, makes it on Form 6765 attached to its timely filed original income tax return, including extensions, and it cannot be made on an amended return. So the return deadlines are also the election deadlines: September 15, 2026 for extended 2025 S corporation and partnership returns, and October 15, 2026 for extended Form 1120 and Form 1040 returns. Sole proprietors can qualify too (IRC 41(h)(3)). The payroll credit eligibility check takes five questions.
Once the election is made, the credit starts with the first calendar quarter that begins after the return is filed. In the IRS example, a calendar-year 2025 return filed April 15, 2026 first takes the credit on the third-quarter 2026 Form 941, due November 2, 2026. Form 8974 then goes with each Form 941 (line 11 on the 2026 form) until the elected amount is used: up to $500,000 a year, first against the employer share of Social Security tax and then Medicare tax (Form 8974 instructions).
Missed credits run on a different clock. A refund claim is due within 3 years from the date the return was filed or 2 years from the date the tax was paid, whichever is later, and a return filed early counts as filed on its due date (IRC 6511, IRC 6513). For a calendar-year C corporation that filed its 2023 return by April 15, 2024, the window for an amended return adding a missed research credit closes April 15, 2027. Form 1120 filers need a formal amended return, and the claim has to identify the business components, the research activities and the total qualified wages, supplies and contract research (IRS research credit claim FAQs). S corporation and partnership credits reach the owners on Schedule K-1, so the owners’ own returns set part of that timing, and a BBA partnership files an administrative adjustment request instead of an amended return.
Credit Recovery reviews open prior years for research credits a preparer missed, and the R&D tax credit calculator gives a first estimate.
Calendar-year S corporations (Form 1120-S) and partnerships (Form 1065) were due March 16, 2026, because March 15 fell on a Sunday. C corporations (Form 1120) and sole proprietors (Form 1040) were due April 15, 2026. With a timely extension, the dates are September 15, 2026 for S corporations and partnerships and October 15, 2026 for C corporations and individuals.
Computed from the rules, because IRS Publication 509 (2027) is not out yet: March 15, 2027 for Forms 1120-S and 1065, and April 15, 2027 for Forms 1120 and 1040. Extended returns are due September 15, 2027 and October 15, 2027.
No. Form 7004 gives an automatic 6-month extension of time to file and has to be filed by the return’s original due date. Tax is still due on the original date, so a corporation should deposit what it expects to owe when it files the extension.
For calendar-year C corporations, on the 15th day of the 4th, 6th, 9th and 12th months: April 15, June 15, September 15 and December 15. None of those dates falls on a weekend or legal holiday in 2026 or 2027, so they hold in both years.
Tuesday, January 18, 2028, computed from IRC 6654 and the weekend and holiday rule: January 15, 2028 is a Saturday and Monday, January 17 is Martin Luther King Jr. Day. The last 2026 payment is due Friday, January 15, 2027.
March 15, 2027 for a calendar-year business. Form 2553 is due no more than 2 months and 15 days after the start of the tax year the election is to take effect, or at any time in the year before. Late-election relief is generally available within 3 years and 75 days of the intended effective date.
With the timely filed original return, including extensions. For calendar-year 2025 that means September 15, 2026 for an extended S corporation or partnership return and October 15, 2026 for an extended C corporation or Form 1040 return. The election cannot be made on an amended return.
Generally 3 years from the date the original return was filed, or 2 years from when the tax was paid if that is later, and a return filed early counts as filed on its due date. A calendar-year C corporation that filed its 2023 return by April 15, 2024 has until April 15, 2027.
Count from your own year end instead of December 31. Forms 1120-S and 1065 are due on the 15th day of the 3rd month after the year ends, Form 1120 on the 15th day of the 4th month, and corporate estimates on the 15th day of the 4th, 6th, 9th and 12th months. C corporations with a June 30 year that began before 2026 use the 3rd month and get a 7-month extension.
The IRS publishes each year’s tax calendar in Publication 509, and the 2027 edition is not out yet. The 2027 dates here apply the due-date rules in the Internal Revenue Code and the weekend and legal holiday rule in IRC 7503. Recheck them when Publication 509 (2027) is released.
On BEG’s separate payroll tax calendar. This page lists Form 941 dates only where a research payroll tax credit needs Form 8974 attached, plus the January deadline for Forms W-2 and 1099-NEC.
Use the download button above the list. After a short form, you get an .ics file that imports into Outlook, Google Calendar or Apple Calendar with a reminder 7 days before each date, plus a .csv file for Excel or Google Sheets.
Tax Review
A 15-minute call with BEG looks at your recent returns and the year ahead. If credits were missed in open years, or next year needs a plan, licensed tax professionals at BEG's tax partner do the work with your CPA. Fee: a share of verified savings, set before work begins. The first review costs nothing.
Tax services are provided by licensed tax professionals under a separate engagement agreement. BEG does not provide tax advice.
