2027 Important Financial and Tax Dates

Estimated tax payments follow the same four-date pattern every year, but the weekday changes where the real due date lands. For 2027, the Q4 2026 payment is due Friday, January 15, 2027. The Q1 payment is due Thursday, April 15, Q2 is due Tuesday, June 15, and Q3 is due Wednesday, September 15. The Q4 2027 payment is the one that shifts: January 15, 2028 is a Saturday and Monday, January 17 is Martin Luther King Jr. Day, so the payment is due Tuesday, January 18, 2028. If you have income without withholding, such as a business, RSU vesting, a large capital gain, or a Roth conversion, a missed installment can trigger an underpayment penalty even when you pay the full balance by April.

Thursday, April 15, 2027 is the busiest day of the year, and it carries items from two different tax years. For the 2026 tax year, it is the Form 1040 due date, the Form 709 gift tax return deadline, the last day to make 2026 IRA and HSA contributions, and the last day for Arizona charitable and school donation credits to count on the 2026 return (see the Arizona credits page for the credit categories). For the 2027 tax year, it is the Q1 estimated payment. It is also the deadline to file Form 4868 for an automatic extension. That extension moves the filing date to Friday, October 15, 2027, but it never moves the payment date. Sole proprietors, single-member LLCs, and calendar-year C corporations also file by April 15.

Business entities that file separate returns run a month earlier. Forms 1120-S and 1065, for S corporations and partnerships, are due Monday, March 15, 2027, and the extended deadline is Wednesday, September 15, 2027. Because March 15 lands on a Monday this year, there is no weekend shift to absorb, so the real due date is the calendar date. That also means S corporation owners deciding on a retirement plan contribution, reasonable compensation, or an entity election need their numbers in hand by late February to leave room for review.

Medicare has three windows that people confuse. The General Enrollment Period runs January 1 to March 31, 2027 (Wednesday), for people who missed their Initial Enrollment Period and need to enroll in Part A and Part B. The Medicare Advantage Open Enrollment Period runs on the same dates, but only for people already in a Medicare Advantage plan, who can switch to another plan or return to Original Medicare. The Annual Enrollment Period runs Friday, October 15 to Tuesday, December 7, 2027, and changes take effect January 1, 2028. Your own Initial Enrollment Period is separate: it is seven months, centered on your 65th birthday month.

Marketplace dates matter for early retirees buying coverage before Medicare. ACA open enrollment for 2028 coverage opens Monday, November 1, 2027. Under the federal rule, the HealthCare.gov window closes December 15 starting with 2027 coverage, so plan to enroll by Wednesday, December 15 for January 1 coverage and confirm the exact window on HealthCare.gov. States that run their own exchanges may use different dates. The premium credit is based on your expected income for the coverage year, so enrolling for 2028 means estimating 2028 income. Roth conversions and capital gains completed in 2027 count toward 2027 income, so coordinate them with your coverage before year-end rather than after.

RMD timing has two tracks. The 2027 RMD for anyone already taking distributions is due Friday, December 31, 2027. RMD age is 73 for people born 1951 to 1959 and 75 for people born 1960 or later. Someone born in 1954 turns 73 in 2027, which makes 2027 their first RMD year. Their first RMD can wait until April 1, 2028, but that is a Saturday, so submit the request by Friday, March 31, 2028 to be safe. Waiting means two RMDs land in 2028, which can push income into a higher bracket and raise Medicare premiums two years later. Run the numbers on both options before choosing.

Year-end is where the decisions live. Friday, December 31, 2027 is the last day for Roth conversions, qualified charitable distributions (the cash must leave the IRA by then), tax-loss and gain harvesting trades, charitable gifts, and annual gifts to family. The annual gift exclusion is $19,000 per recipient for 2026, and the 2027 amount has not been announced. 401(k) deferrals must come out of your last 2027 payroll, and an S corporation owner with a solo 401(k) needs the deferral election in place by that last payroll too. If you inherit an account, September 30 (Thursday) and December 31 of the year after the death matter for identifying designated beneficiaries and for splitting an account into separate inherited accounts.

Start by sorting every date into one of two buckets. Decisions are the dates that change your tax bill and then close permanently: Roth conversions, qualified charitable distributions, charitable gifts, gain and loss harvesting, 401(k) deferrals, and annual gifts. All of them end Friday, December 31, 2027. Paperwork is everything that records what already happened: filing the return, requesting an extension, and funding a prior-year IRA or HSA. Those dates have room into the following spring. A decision deadline deserves attention in October and November, not in April.

Several 2027 milestones are tied to birth year, so check yours. People born in 1954 turn 73 in 2027 and face a first RMD. People born in 1960 reach Social Security full retirement age of 67 in 2027. People born in 1962 turn 65, which starts their Medicare window. People born in 1965 turn 62 and become eligible to claim Social Security early. If you are in one of those groups, the matching date in the calendar below is not optional, and each one is worth a conversation before the window opens.

Some dates you will want to plan around have not been set. Contribution deadlines for the 2027 tax year fall in 2028. Mid-April 2028 is the target for IRA and HSA contributions, but April 15, 2028 is a Saturday, so the IRS sets the exact day. Check the date when the IRS publishes it rather than assuming. Also, a group of figures is missing from this calendar on purpose: the 2027 tax brackets and standard deduction, the 401(k) and IRA limits, the Social Security cost-of-living adjustment (the SSA announces it on October 14, 2026), and the Medicare Part B premium and IRMAA thresholds, which CMS usually announces in the fall. This site publishes a page for each as it is released.

• Assuming the fourth 2027 estimated payment is due January 15, 2028, when that date is a Saturday and the Monday after is a federal holiday, which pushes the real due date to Tuesday, January 18, 2028.
• Treating April 15 as a single deadline when it covers two tax years: the 2026 return and 2026 IRA and HSA contributions, plus the first 2027 estimated payment.
• Filing Form 4868 and believing the extension also covers payment, when the tax owed is still due April 15, 2027.
• Confusing the General Enrollment Period (January to March, for new Part A and Part B enrollment) with the Annual Enrollment Period (October 15 to December 7, for plan changes effective January 1, 2028).
• Waiting until April to do a Roth conversion, a qualified charitable distribution, or a charitable gift for 2027, none of which can be completed after December 31, 2027.
• Delaying a first RMD to the April 1, 2028 deadline without modeling the two-RMDs-in-one-year bracket effect, and then missing the date because April 1 is a Saturday.
• Planning around 2027 limits and premiums that have not been published yet, instead of using the 2026 figures as a placeholder and updating when the new numbers come out.