C Corporation Tax Deadlines
Separate corporate taxpayer filing Form 1120.
Federal return
Due April 15, 2026 with extension to October 15, 2026.
Due: Apr 15, 2026
Extension: Oct 15, 2026
Form: Form 1120
Calendar-year C corps file by the 15th day of the 4th month.
Estimated taxes
Quarterly estimates: Apr 15, 2026, Jun 15, 2026, Sep 15, 2026, Dec 15, 2026.
Due: Apr 15, 2026
State comparison
Select a state to see the detailed deadline page.
FAQ
What happens if my tax deadline falls on a weekend?
The IRS and most states move the due date to the next business day when a deadline lands on a weekend or holiday.
Does an extension give me more time to pay?
Extensions typically give you more time to file, not more time to pay. Any tax owed is still due by the original deadline.
Are state deadlines always the same as federal?
Many states conform to federal due dates, but some states set different deadlines or extensions, so always verify with the state tax agency.