Business Tax Deadlines 2026: Complete Calendar
Missing a tax deadline means penalties, interest, and unnecessary stress. This complete 2026 calendar covers every key date for small business owners across all entity types.
2026 Federal Business Tax Deadlines
Tax deadlines vary based on your business entity type and fiscal year. This calendar covers the most common federal deadlines for small businesses operating on a calendar year (January-December).
Q1: January - March 2026
| Date | Deadline | Who It Applies To |
|---|---|---|
| January 15 | Q4 2025 estimated tax payment | Self-employed, sole proprietors, partners, S-Corp shareholders |
| January 31 | W-2s to employees, 1099-NEC to contractors | All businesses with employees or contractors |
| January 31 | File W-2s and 1099s with SSA/IRS | All businesses with employees or contractors |
| March 16 | S-Corp (Form 1120-S) and Partnership (Form 1065) returns due | S-Corporations, Partnerships, Multi-member LLCs |
Q2: April - June 2026
| Date | Deadline | Who It Applies To |
|---|---|---|
| April 15 | Individual and sole proprietor returns (Form 1040 + Schedule C) | Sole proprietors, single-member LLCs |
| April 15 | C-Corporation returns (Form 1120) | C-Corporations |
| April 15 | Q1 2026 estimated tax payment | Self-employed, sole proprietors, partners, S-Corp shareholders |
| June 15 | Q2 2026 estimated tax payment | Self-employed, sole proprietors, partners, S-Corp shareholders |
Q3: July - September 2026
| Date | Deadline | Who It Applies To |
|---|---|---|
| September 15 | Q3 2026 estimated tax payment | Self-employed, sole proprietors, partners, S-Corp shareholders |
| September 15 | Extended S-Corp and Partnership returns due | S-Corps and partnerships that filed for extension |
Q4: October - December 2026
| Date | Deadline | Who It Applies To |
|---|---|---|
| October 15 | Extended individual and C-Corp returns due | Sole proprietors and C-Corps that filed for extension |
Payroll Tax Deadlines
If you have employees, payroll tax deposits are due on a semi-weekly or monthly basis depending on your total payroll tax liability:
- Monthly depositors: Deposit by the 15th of the following month.
- Semi-weekly depositors: Deposit within 1-3 business days of payroll, depending on your pay day.
- Quarterly returns (Form 941): Due April 30, July 31, October 31, and January 31.
State Tax Deadlines
Most states follow federal deadlines, but there are notable exceptions. Check your state's department of revenue website for specific dates. Key variations include:
- Sales tax: Monthly, quarterly, or annual depending on volume.
- State income tax: Usually follows federal dates but some states differ.
- State payroll taxes: Varies by state.
What Happens If You Miss a Deadline
- Late filing penalty: 5% of unpaid tax per month, up to 25% maximum.
- Late payment penalty: 0.5% of unpaid tax per month, up to 25%.
- Estimated tax penalty: Interest charged on underpayments at the federal short-term rate plus 3%.
Use the business tax calculator to estimate your quarterly payments and review how much to save for taxes to ensure you are always prepared.
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