
LLC Tax Filing Deadlines 2026: A Complete Calendar by Entity Type
A 2026 calendar of LLC tax deadlines by IRS classification — single-member LLCs file Schedule C on April 15, multi-member partnerships and S-corps file Forms 1065 and 1120-S on March 16, C-corps file Form 1120 on April 15. Covers Form 7004 extensions, quarterly estimates, and the $245-per-partner late-filing penalty.








