This is your month-by-month reference for every significant tax deadline in 2027. It covers individual and business filing dates, quarterly estimated payments, retirement contribution deadlines, and extension windows. Bookmark this page and check it at the start of each month -- the penalties for missing deadlines are mechanical and avoidable.
Filing an extension extends only the filing deadline, not the payment deadline. You must still estimate and pay your tax by the original due date (usually April 15). Filing late without an extension triggers a failure-to-file penalty of 5% per month (up to 25%), while paying late triggers a separate 0.5% per month penalty plus interest. These penalties stack.
Most federal tax deadlines fall on the 15th of the relevant month. When the 15th lands on a weekend or federal holiday, the deadline moves to the next business day. State deadlines sometimes differ from federal ones -- always verify your state's specific dates. Technical detail
Penalties for late filing and late payment are separate. Filing late triggers a failure-to-file penalty of 5% of the unpaid tax per month, up to 25%. Paying late triggers a failure-to-pay penalty of 0.5% per month, plus interest. Filing an extension avoids the filing penalty but does not extend the payment deadline -- you must still estimate and pay your tax by the original due date. IRC Section 6651(a)(1) — failure to file penalty; Section 6651(a)(2) — failure to pay penalty.
January 15: Q4 2026 Estimated Tax Payment Due
The fourth quarter estimated payment for the 2026 tax year is due. This covers income earned from September 1 through December 31, 2026. If you file your 2026 return and pay the full balance by January 31, you can skip this payment without penalty. IRS Publication 505; IRC Section 6654(d)(2) — the January 31 filing exception to the Q4 estimated payment.
January 31: Employer Deadlines
- Form W-2 must be furnished to employees and filed with SSA
- Form 1099-NEC (nonemployee compensation) must be furnished to recipients and filed with IRS
- Certain Forms 1099-MISC are due to recipients (others are due February 15)
If you are self-employed or have freelance workers, this is when you should receive or issue the forms needed for tax preparation.
February 2027
February 15: Reclaim Exempt Status on W-4
If you claimed exempt from federal income tax withholding on your W-4 last year, the exemption expires on February 15. You must file a new W-4 with your employer to continue the exempt status or to set new withholding amounts. IRS: About Form W-4; Treas. Reg. Section 31.3402(f)(2)-1(e).
February 28: Paper Filing of Information Returns
If you file information returns (1099s, 1098s) on paper rather than electronically, the deadline is February 28. Electronic filers have until March 31.
March 2027
March 15: S-Corporation and Partnership Returns
- Form 1120-S (S-corporation income tax return) is due
- Form 1065 (partnership return of income) is due
- K-1 schedules must be issued to shareholders/partners by this date
These entity returns are due before individual returns because taxpayers need their K-1s to complete their personal returns. If an extension is filed (Form 7004), the extended deadline is September 15.
March 31: Electronic Filing of Information Returns
Electronic filers of Forms 1099, 1098, and other information returns have until March 31 to file with the IRS (recipients must have received their copies by the January/February deadlines).
April 2027
April 15: The Main Deadline
This is the most consequential date on the tax calendar. Multiple deadlines converge:
- Individual income tax returns (Form 1040) for the 2026 tax year are due
- C-corporation returns (Form 1120) for calendar-year corporations are due
- Trust and estate returns (Form 1041) are due
- Q1 2027 estimated tax payment is due (for the current tax year)
- IRA contributions for the 2026 tax year must be made by this date
- HSA contributions for the 2026 tax year must be made by this date
- Roth IRA contributions for the 2026 tax year must be made by this date
- Individual tax extensions (Form 4868) must be filed by this date to get a six-month extension to October 15
- Gift tax returns (Form 709) for 2026 gifts are due (or extended with the individual return)
IRC Section 6072(a) — individual returns due April 15; Section 6081 — automatic six-month extension on timely request.
April 15: SEP-IRA Contributions (Without Extension)
If you are self-employed and do not file an extension, your SEP-IRA contribution for 2026 must be made by April 15. If you file an extension, the SEP-IRA contribution deadline extends to October 15.
May 2027
May 15: Exempt Organization Returns
- Form 990 (annual return for tax-exempt organizations) is due for organizations with a calendar year-end
- An extension can be filed using Form 8868 for an additional six months
No major individual tax deadlines in May, but this is an excellent month for a financial planning check-in. Review your withholding, update your estimated payment projections based on actual Q1 results, and schedule a [mid-year tax review](/articles/mid-year-tax-check-in) with your CPA.
June 15: Q2 Estimated Tax Payment
The second quarterly estimated payment for 2027 is due. This covers income earned from April 1 through May 31. IRS Publication 505; the Q2 payment covers a two-month period, not three.
June 15: Expat Filing Deadline
U.S. citizens and resident aliens living abroad get an automatic two-month extension to file their individual return and pay their tax. The deadline is June 15 without needing to request an extension, though interest accrues on any unpaid balance from April 15. IRC Section 6081(a); IRS Publication 54 — Tax Guide for U.S. Citizens and Resident Aliens Abroad.
July 2027
No major federal tax deadlines. This is the ideal month for:
- Mid-year tax planning -- you have six months of actual income data, and six months to act
- Withholding review -- run the IRS Tax Withholding Estimator to check whether your W-4 settings will produce the right result by December
- Roth conversion analysis -- if your income is running below projections, discuss conversion opportunities with your CPA while there is time to execute before year-end
August 2027
No major federal tax deadlines. Continue mid-year planning activities started in July.
September 2027
September 15: Q3 Estimated Tax Payment
The third quarterly estimated payment for 2027 is due. This covers income earned from June 1 through August 31.
September 15: Extended S-Corp and Partnership Returns
- Form 1120-S (S-corporation) extended returns are due
- Form 1065 (partnership) extended returns are due
- K-1 schedules for extended filers must be issued by this date
If you are waiting on a K-1 from a partnership or S-corp to finish your personal return, this is the date to watch. Your personal return, on extension, is due October 15 -- giving you just 30 days after receiving a late K-1 to finalize and file.
October 2027
October 15: Extended Individual and C-Corp Returns
- Form 1040 (individual) extended returns are due -- no further extensions available
- Form 1120 (C-corporation) extended returns for calendar-year corporations are due
- Form 1041 (trust and estate) extended returns are due
- SEP-IRA contributions for 2026 are due if you filed an extension
- Form 709 (gift tax) extended returns are due
This is a hard deadline. There is no second extension for individual returns. If you cannot file by October 15, file anyway with your best estimate of any tax owed. Filing late with a balance due triggers both the failure-to-file and failure-to-pay penalties.
If you made a Roth IRA contribution for the 2026 tax year and want to recharacterize it as a traditional IRA contribution (or vice versa), the deadline is October 15, 2027 -- the extended filing deadline, regardless of whether you actually filed an extension. Technical detail
November 2027
No major federal tax deadlines. This is the month for:
- Year-end tax planning -- your CPA should have enough data to project your full-year tax liability and recommend specific actions for December
- Charitable giving decisions -- finalize bunching strategy, initiate stock donations (allow time for brokerage transfers)
- 401(k) deferral adjustments -- calculate remaining payroll cycles and adjust your contribution rate to max out by December 31
December 2027
December 31: Year-End Cutoffs
Multiple strategies must be completed by December 31:
- 401(k) and 403(b) contributions must hit payroll by the last pay date of the year
- Roth conversions must be completed by December 31 (no extensions)
- Tax-loss harvesting trades must settle by December 31 (last trading day, accounting for T+1 settlement)
- Charitable contributions (cash or stock) must be completed by December 31
- Required Minimum Distributions (RMDs) must be taken by December 31 (except for the first RMD year, which can be deferred to April 1 of the following year)
- Flexible Spending Account (FSA) balances must be used (some plans allow a grace period or $640 carryover)
- State and local tax payments for bunching purposes must be made by December 31
For a complete December checklist, see Last-Minute Year-End Tax Moves.
Estimated Tax Payment Summary
| Payment | Covers | Due Date |
|---|---|---|
| Q4 2026 | September - December 2026 | January 15, 2027 |
| Q1 2027 | January - March 2027 | April 15, 2027 |
| Q2 2027 | April - May 2027 | June 15, 2027 |
| Q3 2027 | June - August 2027 | September 15, 2027 |
| Q4 2027 | September - December 2027 | January 15, 2028 |
Technical detail
Contribution Deadline Summary
| Account Type | 2026 Contribution Deadline | 2027 Contribution Deadline |
|---|---|---|
| 401(k) / 403(b) | December 31, 2026 | December 31, 2027 |
| Traditional IRA | April 15, 2027 | April 15, 2028 |
| Roth IRA | April 15, 2027 | April 15, 2028 |
| HSA | April 15, 2027 | April 15, 2028 |
| SEP-IRA | April 15, 2027 (Oct 15 with extension) | April 15, 2028 (Oct 15 with extension) |
| Solo 401(k) - Employee | December 31, 2026 | December 31, 2027 |
| Solo 401(k) - Employer | April 15, 2027 (Oct 15 with extension) | April 15, 2028 (Oct 15 with extension) |