Deadline rule
Annual. The 15th day of the fourth month after the end of the tax year. For calendar-year filers this is April 15.
Due date
The 15th day of the fourth month after the end of the tax year. For calendar-year filers this is April 15.
Who it applies to
C corporation.
Form and agency
Form 1120 · Internal Revenue Service
Notes
An extension of time to file can be requested with Form 7004.
Sources
- IRS — About Form 1120accessed Oct 17, 2026