Whenever a regular tax filing date falls on a Saturday, Sunday, or a legal observed holiday in the District of Columbia, the due date for returns is pushed to the next business day. In 2018, several due dates will be adjusted because of this rule: the Individual and FBAR due date; the C Corporation due date; the Form 1041 due date and extended due date; and the Partnership extended due date.
For calendar year tax returns reporting 2017 information that are due in 2018, the following due dates will apply.
| Form | 2018 Filing Due Date (Tax Year 2017) |
| Form W-2 (electronic or mail) | January 31st |
| Form 1099 | January 31st |
| Form 1065 – Partnerships | March 15th |
| Form 1120S – S Corporations | March 15th |
| Form 1040 – Individuals | April 17th |
| FinCEN 114 – FBAR (will be allowed to extend) | April 17th |
| Form 1041 – Trusts and Estates | April 17th |
| Form 1120 – C Corporations | April 17th |
| Form 990 Series – Tax Exempt Org | May 15th |
| Form 1065 Extended Return | September 17th |
| Form 1120S Extended Return | September 17th |
| Form | Extended Due Dates |
| Form 1041 Extended Return | October 1st |
| Form 1120 Extended Return | October 15th |
| Form 1040 Extended Return | October 15th |
| FinCEN 114 (Extended with Form 1040) | October 15th |
| Form 990 Series Extended Return | November 15th |