When is my business tax return due? It depends on the type of legal entity of your business. If the tax return due date falls on a weekend, the due date is moved to the next following work day; for example, if the 15th of April is on Sunday, the due date is April 16.

Here is a list of the types of business entities and their tax return due dates:

Sole Proprietorship

A sole proprietorship business is an extension of the person running the business, so its year end is December 31, and the tax return due date is the same as the individual's - April 15 of the following year. A sole proprietor fills out Schedule C.

Partnership

A partnership return is filed as an information return on Form 1065, and tax is owed on the individual partner tax return. Thus, the partnership year end is typically December 31, and taxes are due on April 15, when the individual partners file their K-1 forms showing their share of the partnership income.

Multiple-member Limited Liability Company (LLC)

Multiple-member LLCs are taxed as partnerships, so the partnership filing and payment regulations above apply.

Single member LLC

A single member LLC is taxed like a sole proprietorship, so the tax returns are due and taxes are payable on April 15, for the prior year.

Corporations

A corporation that has not filed a Subchapter S election may choose any convenient date as their year end (usually a quarter end date). Corporation tax returns are due and taxes are payable on the 15th day of the third month after the end of the company's fiscal (financial) year. So, a corporation with a year-end date of December 31 must file and pay taxes by March 15; a corporation with a year-end date of September 30 must file and pay taxes by December 15.

Subchapter S Corporations

Corporations which have filed a subchapter S election are taxed on individual income tax returns. So an S corporation must usually take a calendar year end date (December 31) unless the corporation can establish a reasonable business purpose for a different date. The filing date and tax return due date is the same as for other corporations (March 15 for a December 31 year end.)