2026 and 2027 Tax Deadline Calendar

How to Use This Calendar

The dates below apply to calendar-year taxpayers. Fiscal-year entities shift most deadlines to the equivalent month relative to their year end: partnership and S-Corporation returns are due the fifteenth day of the third month after year end, and C-Corporation and individual returns the fifteenth day of the fourth month, with the exception that a C-Corporation with a June 30 year end has a September 15 deadline through 2025 tax years.

Every date has been checked against the weekend and holiday rule in IRC Section 7503. Where a statutory deadline falls on a Saturday, Sunday, or legal holiday, the date shown is the next business day, and the reason is noted. District of Columbia holidays shift nationwide deadlines because the IRS is headquartered there, which is why Emancipation Day occasionally moves the April filing date.

Three deadlines cause more problems than the rest combined, and they are worth setting reminders for now. March 15 or the following business day is both the pass-through return deadline and the Form 2553 deadline for an S-Corporation election effective that year; missing it costs a full year of the election. April 15 is the last day for prior-year IRA and health savings account contributions, and unlike the filing deadline, it does not move with an extension. December 31 is the hard cutoff for nearly every planning action that reduces the current year: property placed in service, retirement plans established, Roth conversions completed, and pre-tax IRA balances rolled into an employer plan before a backdoor Roth.

2026: January Through March

2026: April Through June

2026: July Through October

2026: November and December

2027 Federal Deadlines

Extensions, Penalties, and What They Cost

An extension moves the filing deadline, never the payment deadline. Form 4868 gives individuals six additional months to file, Form 7004 does the same for business returns, and Form 8868 covers exempt organizations. Tax owed remains due on the original date, and interest under IRC Section 6601 runs from that date at the federal short-term rate plus three percentage points, compounded daily.

The penalties are asymmetric, and understanding the difference changes behavior. The failure to file penalty under IRC Section 6651(a)(1) is 5% of the unpaid tax per month or part of a month, capped at 25%. If a return is more than 60 days late, the minimum penalty is the lesser of $510 for 2025 returns or 100% of the tax due. The failure to pay penalty under IRC Section 6651(a)(2) is 0.5% per month, also capped at 25%. Filing late is ten times more expensive than paying late, which means an extension should always be filed even when the balance cannot be paid.

Information return penalties scale by lateness. For 2025 returns, a Form W-2 or 1099 filed up to 30 days late carries $60 per form, up to $130 if filed by August 1, and $340 if later or not filed, with higher amounts for intentional disregard and no cap in that case. For a business issuing 50 contractor 1099s, missing the deadline entirely is a $17,000 exposure before considering the corresponding payee statement penalties.

Partnership and S-Corporation late filing penalties are assessed per owner per month: $245 per partner or shareholder per month for up to 12 months for 2025 returns. A four-owner partnership filing six months late owes $5,880 regardless of whether any tax was due.

First Time Abate relief is available for failure to file, failure to pay, and failure to deposit penalties where the taxpayer has a clean compliance history for the prior three years and all required returns are filed. It does not apply to the estimated tax penalty under IRC Section 6654, which follows its own waiver rules described on our quarterly estimates page.

Year-End Planning Cutoffs Worth Calendaring

Most tax reduction happens before December 31, not at filing. These are the actions that expire with the calendar year and cannot be recovered in the spring.

Property placed in service. Bonus depreciation and Section 179 require the asset to be placed in service, meaning ready and available for its intended use, by December 31. A cost segregation study can be completed after year end for a property placed in service during the year, but the property itself must have been in service. This is the constraint that drives fourth-quarter real estate closings.

Retirement plan establishment. A new 401(k), cash balance, or defined benefit plan generally must be adopted by the last day of the plan year to allow employee deferrals for that year, though the SECURE Act permits a plan to be adopted by the employer's tax filing deadline including extensions for employer contributions only. Cash balance and defined benefit plans require actuarial work that takes weeks, so November is the practical deadline, not December 31.

Roth conversions. A conversion must be completed by December 31 to count for that year. There is no extension and, since 2018, no recharacterization of conversions.

Clearing pre-tax IRA balances. The pro-rata rule for a backdoor Roth is measured on December 31 balances, so a rollover into an employer plan must settle before year end.

Required minimum distributions. Due December 31, except for the first RMD year, which may be delayed to April 1 of the following year at the cost of taking two distributions in that year.

Charitable contributions. Cash gifts must be paid, and appreciated securities must be transferred and settled, by December 31. Donor advised fund contributions are deductible when the fund receives them, which makes them useful for December decisions.

Capital gain and loss harvesting. Trades must settle by the last business day. Wash sale rules under IRC Section 1091 disallow a loss where substantially identical securities are purchased within 30 days before or after the sale.

Entity and payroll adjustments. Owner compensation true-ups, S-Corporation shareholder health insurance added to W-2 wages, and increased withholding to cure a quarterly estimate shortfall all require payroll to be run before year end.

We run a year-end planning cycle with clients in October and November so these items are executed rather than discovered in April. Our year-end checklists cover the full sequence.