Holidays and Quarters
Saturday, Sunday, or Legal Holiday. Generally, if a due date for performing any act for tax purposes falls on a Saturday, Sunday, or legal holiday, the act is considered to be performed timely if it is performed no later than the next day that isn't a Saturday, Sunday, or legal holiday. The term legal holiday includes any legal holiday in the District of Columbia. You must also make any adjustments for statewide legal holidays, as discussed below.

Legal Holidays. The federal legal holidays are listed below:

• New Year's Day
• Birthday of Martin Luther King, Jr.
• Washington's Birthday
• District of Columbia Emancipation Day
• Memorial Day
• Independence Day
• Labor Day
• Columbus Day
• Veterans Day
• Thanksgiving Day
• Christmas Day

Statewide Legal Holidays. A statewide legal holiday delays a due date for filing a federal tax return only if the IRS office where you are required to file the tax return is located in that state. However, if you are a resident of Massachusetts or Maine, Patriots' Day (April 18) delays the due date for filing a federal income tax return regardless of where you are required to file.

Quarters:

• First Quarter: The first quarter of a calendar year is made up of January, February, and March.
• Second Quarter: The second quarter of a calendar year is made up of April, May, and June.
• Third Quarter: The third quarter of a calendar year is made up of July, August, and September.
• Fourth Quarter: The fourth quarter of a calendar year is made up of October, November, and December.

Individuals
Form 1040. This form is due on the 15th day of the 4th month after the end of your tax year. Form 4868 is used to request an extension of time to file Form 1040.

Estimated tax payments (Form 1040-ES). Payments are due on the 15th day of the 4th, 6th, and 9th months of your tax year and on the 15th day of the 1st month after your tax year ends.

Partnerships
Form 1065. This form is due on the 15th day of the 3rd month after the end of the partnership's tax year. Provide each partner with a copy of their Schedule K-1 (Form 1065) or substitute Schedule K-1 (Form 1065) by the 15th day of the 3rd month after the end of the partnership's tax year. Form 7004 is used to request an automatic 6-month extension of time to file Form 1065.

Form 1065-B (electing large partnerships). This form is due on the 15th day of the 3rd month after the end of the partnership's tax year. Provide each partner with a copy of their Schedule K-1 (Form 1065-B) or substitute Schedule K-1 (Form 1065-B) by the first March 15 following the close of the partnership's tax year. This due date for filing Schedule K-1 (Form 1065-B) applies even if the partnership requests an extension of time to file Form 1065-B. Form 7004 is used to request an automatic 6-month extension of time to file Form 1065-B.

Corporations and S Corporations
Form 1120 (or Form 7004). This form is due on the 15th day of the 4th month after the end of the corporation’s tax year. However, a corporation with a fiscal tax year ending June 30 must file by the 15th day of the 3rd month after the end of its tax year. A corporation with a short tax year ending anytime in June will be treated as if the short year ended on June 30, and must file by the 15th day of the 3rd month after the end of its tax year.

Form 7004 is used to request an automatic 6-month extension of time to file Form 1120. However, corporations with a fiscal tax year ending June 30, or a short tax year treated as if the short year ended June 30 will use Form 7004 to request an automatic 7-month extension of time to file Form 1120.

Form 1120S (or Form 7004). This form is due on the 15th day of the 3rd month after the end of the corporation's tax year. Provide each shareholder with a copy of their Schedule K-1 (Form 1120S) by the 15th day of the 3rd month after the end of the corporation's tax year. Form 7004 is used to request an automatic 6-month extension of time to file Form 1120S.

Estimated tax payments. Payments are due on the 15th day of the 4th, 6th, 9th, and 12th months of the corporation's tax year.

Form 2553. This form is used to choose S corporation treatment. It is due no more than two months and 15 days after the beginning of the tax year the election is to take effect or at any time during the preceding tax year.