Tax Year
The 12-month accounting period for calculating and filing taxes. For most individuals, the tax year is the calendar year (January 1 through December 31).
A tax year is the annual period covered by a tax return. Most individual taxpayers and many businesses use the calendar year — January 1 through December 31. Some businesses may choose a fiscal year that ends on the last day of a month other than December, but individuals almost always use the calendar year.
Your tax year determines when income is reported and when deductions are taken. Under the cash method of accounting (used by most individuals), income is reported when received and expenses are deducted when paid. Under the accrual method (used by some businesses), income is reported when earned and expenses when incurred, regardless of when cash changes hands.
Tax returns for a calendar year are due on April 15 of the following year (or the next business day if April 15 falls on a weekend or holiday). For example, your 2025 tax year return covers income earned from January 1 to December 31, 2025, and is due April 15, 2026.
Related Terms
Fiscal Year
A 12-month accounting period that ends on the last day of any month other than December. Used mainly by businesses and some trusts, not by individual taxpayers.
Tax Return
The form(s) you file with the IRS to report income, claim deductions and credits, and calculate your tax liability or refund. For individuals, this is Form 1040.
Extension
A request to push your tax return filing deadline from April 15 to October 15. An extension gives more time to file but not more time to pay any taxes owed.