Business Tax Deadline Calendar
Select your business type and get a personalized calendar of every federal and state tax deadline you need to know in 2026.
Business Information
Entity Type
Single-Member LLC
Total Deadlines
7
Critical Deadlines
7
Q1 (Jan-Mar)
1099-NEC Due to Contractors & IRS
Send 1099-NEC to each contractor paid $600+ and file with IRS.
Form: Form 1099-NEC
Estimated Tax Payment — Q4 (Sep-Dec)
Pay 25% of your estimated annual tax liability to avoid underpayment penalties.
Form: Form 1040-ES
Q2 (Apr-Jun)
Individual Income Tax Return
File Schedule C with your Form 1040. Includes self-employment tax (Schedule SE).
Form: Form 1040 + Schedule C + Schedule SE
Estimated Tax Payment — Q1 (Jan-Mar)
Pay 25% of your estimated annual tax liability to avoid underpayment penalties.
Form: Form 1040-ES
CA State Income Tax Return
File state income tax return. Most states follow federal deadlines.
Form: State income tax form
Estimated Tax Payment — Q2 (Apr-May)
Pay 25% of your estimated annual tax liability to avoid underpayment penalties.
Form: Form 1040-ES
Q3 (Jul-Sep)
Estimated Tax Payment — Q3 (Jun-Aug)
Pay 25% of your estimated annual tax liability to avoid underpayment penalties.
Form: Form 1040-ES
Tax Planning Tips
- • Set calendar reminders at least 2 weeks before each deadline.
- • Consider S-Corp election (Form 2553) if net income exceeds $50,000 to reduce self-employment tax.
- • Check CA state-specific deadlines — some states have different due dates.
- • File for extension if needed (Form 7004 for business, Form 4868 for personal) — but pay estimated tax by the original deadline.
- • Collect W-9 from all contractors before making payments to ensure timely 1099 filing.
2026 Federal Tax Deadlines by Business Type
Missing a tax deadline can cost you penalties starting at 5% per month on unpaid taxes (failure-to-file) plus 0.5% per month interest (failure-to-pay). The maximum failure-to-file penalty reaches 25% of your tax due. Estimated tax penalties run about 8% annualized in 2026. A personalized tax calendar eliminates surprises and gives you time to prepare.
| Entity Type | Tax Return Form | Filing Deadline | Extension Deadline |
|---|---|---|---|
| Sole Proprietorship | Schedule C (Form 1040) | April 15 | October 15 |
| Single-Member LLC | Schedule C (Form 1040) | April 15 | October 15 |
| Partnership / Multi-Member LLC | Form 1065 | March 15 | September 15 |
| S Corporation | Form 1120-S | March 15 | September 15 |
| C Corporation | Form 1120 | April 15 | October 15 |
Quarterly Estimated Tax Deadlines
| Quarter | Period Covered | Payment Due | Form |
|---|---|---|---|
| Q1 | January - March | April 15, 2026 | 1040-ES / 1120-W |
| Q2 | April - May | June 15, 2026 | 1040-ES / 1120-W |
| Q3 | June - August | September 15, 2026 | 1040-ES / 1120-W |
| Q4 | September - December | January 15, 2027 | 1040-ES / 1120-W |
The safe harbor rule lets you avoid underpayment penalties by paying at least 100% of last year's tax liability (110% if AGI exceeds $150,000) or 90% of the current year's liability, whichever is less.
Payroll Tax Deadlines for Employers
| Form | What It Covers | Frequency | Due Date |
|---|---|---|---|
| Form 941 | Income tax + Social Security + Medicare withheld | Quarterly | Last day of month after quarter ends |
| Form 940 | Federal Unemployment Tax (FUTA) | Annual | January 31 |
| W-2 | Employee wage and tax statement | Annual | January 31 |
| 1099-NEC | Contractor payments of $600+ | Annual | January 31 |
| Payroll deposits | Withheld taxes | Monthly or semi-weekly | Based on total tax liability |
Frequently Asked Questions
What happens if I miss a quarterly estimated tax payment?
The IRS charges an underpayment penalty calculated at the federal short-term rate plus 3 percentage points (approximately 8% in 2026). The penalty applies to the amount underpaid for each quarter from the due date until the payment is made or until April 15 of the following year. You can make a late payment at any time to stop the penalty from growing — there's no additional late filing penalty for estimated payments.
Do I still need to pay taxes on time if I file an extension?
Yes. An extension gives you extra time to file your return, not extra time to pay. You must estimate and pay your tax liability by the original deadline (March 15 or April 15). If you underpay, you'll owe interest and a failure-to-pay penalty of 0.5% per month on the balance. Filing the extension itself avoids the much steeper failure-to-file penalty (5% per month).
Related tools: Quarterly Tax Calculator and Payroll Tax Calculator.