United States Tax & Filing Deadlines
Every United States statutory deadline a founder needs to know. Penalties, checklists and source links to Internal Revenue Service (IRS) and State Secretary of State (varies by state).
Form 1120 — C-Corporation Annual Return
Annual federal income tax return for US C-corporations. Due 15 April for calendar-year filers (15th day of the 4th month after fiscal year-end). 6-month automatic extension via Form 7004 — extension is to file, not to pay.
Form 1120-S — S-Corporation Annual Return
Annual federal income tax return for US S-corporations. Due 15 March for calendar-year filers. 6-month automatic extension via Form 7004 to 15 September.
Form 1065 — Partnership Return
Annual federal information return for partnerships and multi-member LLCs taxed as partnerships. Due 15 March for calendar-year filers. 6-month extension via Form 7004 to 15 September.
Form 941 — Quarterly Employer Tax Return
Quarterly federal payroll tax return for employers with W-2 employees. Reports Social Security, Medicare and federal income tax withholding. Due last day of month following quarter end.
Form 1099-NEC — Contractor Reporting
Annual reporting of non-employee compensation of $600+ paid to independent contractors. Issuer must send 1099-NEC to recipient AND IRS by 31 January following the calendar year.
Form W-2 — Employee Wage Statement
Annual statement of wages and taxes withheld for each W-2 employee. Must be sent to employees AND filed with the Social Security Administration by 31 January following the calendar year.
Q1 Estimated Tax — 15 April
First quarter federal estimated tax payment for self-employed people, freelancers, partners and others without sufficient withholding. Covers 1 January – 31 March income.
Beneficial Ownership Information (BOI) Report
Federal beneficial ownership reporting under the Corporate Transparency Act, filed with FinCEN. Required for most US LLCs, corporations and similar entities. New entities: report within 30 days of formation. Existing entities: typically due 1 January 2025 (subject to ongoing legislative/court changes).