US Business Tax Deadlines (2026)
Verify annually — figures adjust
These are the recurring federal deadlines for a calendar-year filer. Dates and the forms behind them should be confirmed against irs.gov for the current year.
| Date | Who it applies to | What is due | Form |
|---|---|---|---|
| January 15 | Individuals, sole proprietors | Fourth-quarter estimated tax for the prior year | Form 1040-ES |
| January 31 | Employers | Wage statements to employees and contractors, and to the government | Forms W-2, 1099-NEC |
| March 15 | S-corporations and partnerships (calendar year) | Income tax return, or an extension; Schedules K-1 to owners | Forms 1120-S, 1065 |
| April 15 | C-corporations and individuals (calendar year) | Income tax return, or an extension; first-quarter estimated tax | Forms 1120, 1040 |
| June 15 | Individuals | Second-quarter estimated tax | Form 1040-ES |
| September 15 | S-corporations, partnerships, individuals | Extended pass-through returns; third-quarter estimated tax | Forms 1120-S, 1065, 1040-ES |
| October 15 | C-corporations and individuals | Extended income tax returns | Forms 1120, 1040 |
When a deadline falls on a Saturday, Sunday, or legal holiday, it moves to the next business day. Fiscal-year filers follow the same pattern relative to their own year end. This calendar covers federal dates only; state deadlines appear on each state’s page.
Mena Hemaia, CPA, CIA
Chief Executive Officer, Accountack — West Palm Beach, Florida
If you want to know which of these apply to your business specifically, that is a conversation about your actual numbers — not a seminar example.
Or start with the Free Cash Clarity Audit — A no-cost review of where your business stands and what a planning engagement would target — the firm's own named starting point.
20 minutes with an Accountack advisor. If a technical review is worth your time, the next step is a workshop with Mena — and if there is nothing material to do, he will say so.