What Is a Fiscal Tax Year End Date? Eligibility, Deadlines, and Changes

A fiscal tax year end date is the final day of the 12-month accounting period a business uses to calculate taxable income, and it falls on the last day of any month other than December. The calendar year, running January 1 through December 31, is the default the IRS assigns to anyone who does not keep books on a different cycle. Everything else the IRS tracks for you, when your return is due, when estimated payments are owed, and how income gets allocated across years, flows from this date.¹

Calendar Year or Fiscal Year

Federal tax law recognizes two main annual accounting periods. The calendar year is the January-through-December cycle. A fiscal year is any 12-month period ending on the last day of a month other than December. A ski resort might pick September 30 because that sits between the summer off-season and the winter rush, letting the books close during a quiet stretch with fewer transactions to cut off.

Whichever you adopt, your tax year must match the accounting period you actually use to keep your records. You cannot keep books on a calendar basis and file a fiscal-year return. The year-end becomes official the moment you file your first federal income tax return using that period, and from then on you report on the same cycle every year unless the IRS approves a change.²

The 52/53-Week Option

Some businesses prefer a year that always ends on the same weekday rather than the same calendar date. The tax code allows a 52/53-week year ending on the last time a chosen weekday falls in a month, or on the occurrence of that weekday closest to month-end. The year contains either 364 or 371 days depending on how the calendar lines up, which keeps internal reporting periods uniform in length.³

Who Can Choose a Fiscal Year

How much freedom you have in picking a year-end depends almost entirely on your business structure. Pass-through entities face tight restrictions because a mismatched year-end can let owners defer income for close to a full year. Entities taxed on their own income face fewer constraints.

C Corporations

C corporations have the most flexibility. A C corporation can adopt any calendar or fiscal year that matches its books, with no special IRS approval needed beyond filing the first return on that basis.

Personal Service Corporations

A personal service corporation is a C corporation whose principal activity is providing services in fields such as health care, law, engineering, architecture, accounting, actuarial science, performing arts, or consulting, and whose employee-owners perform a substantial share of the work. These corporations must use a calendar year unless they can demonstrate a business purpose for a different year-end or elect a fiscal year under Section 444.⁴

Partnerships

Partnerships must align their year-end with their owners’ years through a hierarchy of tests. If partners who together own more than 50 percent of profits and capital share the same tax year, the partnership must use that year. If no single year clears that majority-interest threshold, the partnership must use the year of all its principal partners (anyone holding 5 percent or more). If that test also fails, the partnership defaults to whichever year-end produces the smallest total deferral of income to its partners.⁵

A partnership can escape that result only by proving a business purpose to the IRS or by making a Section 444 election.

S Corporations

S corporations must use a calendar year by default. The statute calls this the “permitted year,” meaning a year ending December 31 or any other year the corporation can justify with a business purpose. Income deferral by itself does not count.⁶ A Section 444 election is the other way out.

Sole Proprietorships and Single-Member LLCs

A sole proprietorship or single-member LLC treated as a disregarded entity must use the same tax year as its owner. Since most individual owners are on a calendar year, these businesses end up with a December 31 year-end. They cannot elect a separate fiscal year because the IRS does not treat them as separate taxpayers.²

Trusts and Estates

Most trusts are stuck on the calendar year. The code is blunt: the taxable year of any trust is the calendar year, with exceptions only for tax-exempt and certain charitable trusts.⁷ Estates are the exception. An estate can choose any fiscal year ending within 12 months of the date of death. A qualified revocable trust that elects to be treated as part of the estate under Section 645 can use the estate’s fiscal year instead of a calendar year.⁸

The Section 444 Workaround

Partnerships, S corporations, and personal service corporations that want a fiscal year but cannot pass a business-purpose test have a fallback. A Section 444 election lets the entity pick a year-end that creates no more than three months of deferral compared to the required year. For an entity whose required year is the calendar year, that means September 30, October 31, or November 30.⁹

The trade-off is a required annual payment that approximates the tax benefit owners get from the deferral. Partnerships and S corporations making this election file Form 8752 and pay an amount based on net income and the highest individual tax rate plus one percentage point.¹⁰ For election years beginning in 2025, the filing and payment are due May 15, 2026, and missing the deadline triggers a penalty of 10 percent of the underpayment.¹¹

The election terminates if the entity becomes part of a tiered ownership structure, such as a partnership that later becomes a partner in another partnership, and the entity cannot make a new one.⁹

Filing Deadlines Tied to Your Year-End

Your year-end directly controls when the return is due. The timing differs by entity:

C corporations: Due by the 15th day of the fourth month after the fiscal year ends. A March 31 year-end puts the return on July 15. Corporations with a June 30 fiscal year-end are the exception and file by September 15 (the 15th day of the third month).¹²
Partnerships and S corporations: Due by the 15th day of the third month after the fiscal year ends. A December 31 year-end means March 15; June 30 means September 15.¹³
Individuals: Returns are due April 15. Individuals must use a calendar year.¹³

When a due date falls on a weekend or legal holiday, the deadline shifts to the next business day. Any of these entities can request an automatic six-month extension by filing Form 7004 before the original due date. The extension buys time to file the return, not time to pay any tax owed.¹⁴

Changing a Year-End After You’ve Set One

Once your first return locks in a tax year, switching to a different one requires IRS approval through Form 1128.¹⁵

Some changes qualify for automatic approval under published revenue procedures. A C corporation switching to a calendar year, for instance, can often get automatic approval with no user fee, provided it meets every condition in the applicable procedure. You still file Form 1128, and you still file it by the due date of the short-period return that the change produces.

Changes that do not qualify for automatic approval require a private letter ruling. You submit Form 1128 with a detailed explanation of the business purpose for the new year-end, and the IRS charges a $1,500 user fee.¹⁶ The process takes months.

Any year-end change leaves a gap between the old year-end and the new one, and that gap has to be reported on a short-period return.¹⁷ The tax on that short period is not just the tax on the income that fell in those months. The IRS requires you to annualize the income first, compute tax on the annualized figure, then prorate it back down, which prevents a shortened period from dropping you into an artificially low bracket.

1
GovInfo. 26 USC 441 – Period for Computation of Taxable Income
2
Internal Revenue Service. Publication 538, Accounting Periods and Methods
3
eCFR. 26 CFR 1.441-2 – Election of Taxable Year Consisting of 52-53 Weeks
4
eCFR. 26 CFR 1.441-3 – Taxable Year of a Personal Service Corporation
5
Office of the Law Revision Counsel. 26 USC 706 – Taxable Years of Partner and Partnership
6
Office of the Law Revision Counsel. 26 USC 1378 – Taxable Year of S Corporation
7
Office of the Law Revision Counsel. 26 USC 644 – Taxable Year of Trusts
8
Office of the Law Revision Counsel. 26 USC 645 – Certain Revocable Trusts Treated as Part of Estate
9
Office of the Law Revision Counsel. 26 USC 444 – Election of Taxable Year Other Than Required Taxable Year
10
Office of the Law Revision Counsel. 26 USC 7519 – Required Payments for Entities Electing Not to Have Required Taxable Year
11
Internal Revenue Service. Instructions for Form 8752
12
Internal Revenue Service. Starting or Ending a Business
13
Office of the Law Revision Counsel. 26 USC 6072 – Time for Filing Income Tax Returns
14
Internal Revenue Service. About Form 7004, Application for Automatic Extension of Time to File Certain Business Income Tax, Information, and Other Returns
15
Internal Revenue Service. About Form 1128, Application to Adopt, Change or Retain a Tax Year
16
Internal Revenue Service. Schedule of IRS User Fees
17
Office of the Law Revision Counsel. 26 USC 443 – Returns for a Period of Less Than 12 Months