California small businesses face federal IRS deadlines and California state deadlines that sometimes fall on different dates. Missing a tax filing for California businesses triggers IRS penalties, California FTB interest charges, and, in some cases, automatic suspension of your business.
If your California business needs a clear tax calendar, this guide breaks down the deadlines, payments, forms, and filing rules that small business owners need to track, organized by month, entity type, and obligation.
Key Takeaways
- California LLCs owe an $800 minimum franchise tax every year, due by the 15th day of the 4th month of the tax year (April 15 for calendar-year LLCs).
- S-Corp and partnership federal returns are due March 17, 2026. C-Corp and individual returns are due April 15, 2026.
- Quarterly estimated tax payments California business owners must make fall on April 15, June 16, September 15, 2026, and January 15, 2027.
- W-2s and 1099-NECs must reach recipients by January 31, 2026.
- Focus CPA Group (Brea, CA) manages deadline tracking, tax planning, and compliance for California small businesses year-round.
Why California Businesses Must Track Tax Deadlines Carefully in 2026
Tax filing deadlines for California small business owners in 2026 are more complex than in most states. The IRS sets federal deadlines. The California FTB sets state deadlines. The EDD sets payroll deadlines. The CDTFA sets sales tax deadlines. These do not always align.
Financial and Legal Consequences of Missing Deadlines
Missing a federal deadline triggers an IRS failure-to-file penalty of 5% of unpaid tax per month, up to 25% (IRS Publication 334). A failure-to-pay penalty adds 0.5% per month on top. California’s FTB charges a 5% late-filing penalty plus 0.5% per month for unpaid taxes.
LLCs that miss estimated franchise tax payments face a 25% underpayment penalty. For payroll taxes, late federal deposits cost between 2% and 15%, depending on how many days the payment is overdue (IRS Form 941 instructions). The IRS also charges interest on unpaid balances from the original due date, compounding daily.
Complete 2026 Tax Filing Calendar for California Small Businesses
The California business tax calendar 2026 below covers every major federal and state deadline by month. Use this as your master reference.
January 2026 Important Tax Deadlines
- January 15: Fourth-quarter 2025 estimated tax payment due (IRS Form 1040-ES). California FTB fourth installment is also due.
- January 31: W-2s must be provided to employees and filed with the SSA. 1099-NEC forms must reach recipients. Federal Form 940 (FUTA) annual return due. California EDD DE 9C quarterly wage report due.
- January 31: Fourth-quarter 2025 payroll tax return (Form 941) due if you deposited all taxes on time.
March 2026 Business Tax Deadlines
- March 17: S-Corporation federal returns (Form 1120-S) due for calendar-year filers. Partnership federal returns (Form 1065) due. California FTB S-Corp and partnership returns follow the same date.
- March 17: Last day to file Form 7004 for a six-month extension on S-Corp and partnership returns. Extension does not delay payment due dates.
April 2026 Federal and California Tax Deadlines
April is the busiest month on the small business tax due dates California calendar.
- April 15: Federal individual income tax return (Form 1040) due, including Schedule C for sole proprietors.
- April 15: California LLC tax deadline. California LLCs must pay the $800 minimum franchise tax for 2026 by this date (FTB Form 3522).
- April 15: First-quarter 2026 estimated tax payment due (IRS Form 1040-ES and California FTB Form 540-ES).
- April 15: C-Corporation federal return (Form 1120) due for calendar-year filers. California FTB corporate return is also due.
- April 15: Last day to file Form 7004 for C-Corp and individual extension requests.
June 2026 Estimated Tax Payment Deadlines
- June 16: Second-quarter IRS filing dates, 2026 estimated tax payment due (Form 1040-ES). California FTB’s second installment is also due June 16. Note: California skips the third federal installment. California’s second installment covers a larger portion than the federal payment.
September 2026 Estimated Tax Requirements
- September 15: Third-quarter federal estimated tax payment due (Form 1040-ES). S-Corp and partnership extended returns are also due today if Form 7004 was filed in March.
- September 15: California FTB third estimated installment due.
October 2026 Extension Filing Deadlines
- October 15: Extended individual and C-Corp federal returns due. California extended personal income tax returns due. If you filed Form 7004 or an FTB extension in April, this is your final deadline to file.
December 2026 Year-End Tax Planning Checklist
December is not a filing month, but it is the most important California tax planning month of the year for small businesses. Actions taken before December 31 directly affect your 2026 tax return.
- Max out Solo 401(k) or SEP-IRA contributions before year-end
- Prepay January 2027 business expenses where allowed
- Place qualifying equipment in service for Section 179 deduction (IRS Publication 946)
- Review S-Corp salary-to-distribution ratio before the year closes
- Write off any uncollectible accounts receivable
Federal IRS Filing Dates Every California Business Should Know
IRS filing dates for 2026 vary by business entity type. Here is the complete breakdown.
Sole Proprietorship Tax Return Deadlines
Sole proprietors file Schedule C with their Form 1040. The deadline is April 15, 2026. An extension (Form 4868) pushes the filing date to October 15, 2026. Tax owed is still due April 15.
Partnership Filing Requirements and Due Dates
Partnerships file Form 1065 by March 17, 2026. Each partner receives a Schedule K-1 by that date. An extension via Form 7004 moves the deadline to September 15, 2026 (per IRS Form 1065 instructions).
S Corporation Tax Deadlines
S-Corp returns (Form 1120-S) are due March 17, 2026. A Form 7004 extension moves the deadline to September 15, 2026. The S-Corp itself does not pay federal income tax, but each shareholder reports income via Schedule K-1.
C Corporation Tax Return Deadlines
C-Corp returns (Form 1120) are due April 15, 2026, for calendar-year corporations. An extension via Form 7004 moves the deadline to October 15, 2026. C-Corps also make quarterly estimated tax payments using Form 1120-W.
California LLC Tax Deadlines and Franchise Tax Requirements
California LLC tax deadline April rules are unique to California. No other state imposes a similar structure.
Annual LLC Filing Obligations
California LLCs must file Form 568 (LLC Return of Income) annually. For calendar-year LLCs, Form 568 is due April 15, 2026. An automatic six-month extension moves this to October 15, 2026, but the $800 payment is still due April 15.
California $800 Franchise Tax Requirements
Every California LLC, S-Corp, and corporation pays a minimum $800 annual franchise tax to the FTB, regardless of profit or revenue. For LLCs formed in 2021 or later, the first year’s $800 is waived. For all other years, the $800 is due by the 15th day of the 4th month of the tax year (April 15 for calendar-year LLCs), per the California FTB LLC tax booklet.
LLC Fee Payment Deadlines
LLCs with total California annual gross receipts over $250,000 owe an additional LLC fee. The fee ranges from $900 (receipts of $250,000-$499,999) to $11,790 (receipts over $5 million). This fee is paid with Form 3536 by June 15, 2026, for calendar-year LLCs (FTB Form 3536 instructions).
Payroll Tax Deadlines for California Employers
California employers withhold federal income tax, Social Security, Medicare (FICA), California state income tax, and California SDI from employee wages. Monthly bookkeeping tasks for employers include reconciling payroll records against tax deposit confirmations every month.
Employers must deposit federal payroll taxes through the IRS EFTPS setup for 2026 on a monthly or semi-weekly schedule based on prior-year tax liability (IRS Publication 15, Circular E). Late EFTPS deposits trigger penalties immediately.
W-2 and 1099 Filing Deadlines
- January 31, 2026: W-2s to employees and Copy A to SSA
- January 31, 2026: Form 1099-NEC to contractors paid $600 or more in 2025
- February 28, 2026: Paper Forms 1099-MISC (non-NEC) due to the IRS
- March 31, 2026: Electronic 1099-MISC filing deadline
State Payroll Reporting Requirements
California employers file quarterly with the EDD: Form DE 9 (Quarterly Contribution Return) and Form DE 9C (Quarterly Wage and Withholding Report). Both are due January 31, April 30, July 31, and October 31 each year (California EDD Employer’s Guide DE 44).
Estimated Tax Payment Deadlines for Business Owners
Any sole proprietor, partner, S-Corp shareholder, or self-employed individual who expects to owe $1,000 or more in federal tax (or $500 or more in California state tax) after withholding must make quarterly estimated tax payments, as California business rules require (IRS Publication 505, Form 1040-ES instructions).
Quarterly Payment Schedule for 2026
California requires 30% of estimated tax by Q1, 40% by Q2, 0% by Q3, and 30% by Q4. Federal splits are 25% per quarter.
| Payment | Period Covered | Federal Due Date | California Due Date |
| Q1 | Jan 1 – Mar 31 | April 15, 2026 | April 15, 2026 |
| Q2 | Apr 1 – May 31 | June 16, 2026 | June 16, 2026 |
| Q3 | Jun 1 – Aug 31 | September 15, 2026 | September 15, 2026 |
| Q4 | Sep 1 – Dec 31 | January 15, 2027 | January 15, 2027 |
Common California Business Tax Filing Mistakes
Common California accounting mistakes that small businesses make repeatedly include these, and all of them are avoidable with proper planning.
- Missing the April 15 LLC franchise tax payment. Most business owners confuse the filing deadline with the payment deadline. The $800 is due April 15, even if you file an extension.
- Skipping quarterly estimated payments. Underpayment penalties apply even if you pay everything by April 15.
- Misclassifying workers as contractors. California’s AB 5 law applies strict tests. Getting this wrong triggers EDD back taxes, penalties, and interest.
- Not registering for CDTFA. Businesses that sell taxable goods in California must collect and remit sales tax. Failing to register triggers back liability from the date sales began.
- Ignoring the FTB LLC fee. The $900-$11,790 LLC fee is separate from the $800 franchise tax and due on a different date.
- Using personal accounts for business. Mixed transactions cause deduction losses and extend audit exposure.
Tax Extensions: What California Businesses Need to Know
Form 7004 grants an automatic six-month extension for business returns. Form 4868 grants an automatic six-month extension for individual returns. Both must be filed by the original due date. Timely tax filing of the extension form itself is what activates the extended deadline (IRS Form 7004 instructions).
California Extension Guidelines
California grants an automatic six-month extension for business and personal returns without requiring a separate form, as long as 100% of tax owed is paid by the original deadline (California FTB Extension guidance). If tax is still owed, file FTB Form 3519 (individuals) or 3539 (businesses) with payment.
Extension Does Not Mean Delayed Payment
An extension moves your filing deadline. It does not move your payment deadline. Tax owed April 15 is still owed April 15, with interest accruing from that date if unpaid. If you cannot pay in full, the California FTB payment plan program (FTB Installment Agreement) allows monthly payments on the balance owed.
How Focus CPA Helps California Businesses Stay Compliant Year-Round
Focus CPA Group tracks every federal and California deadline for each client across all entity types. Our firm builds a California business tax calendar for 2026 specific to each client’s structure, payroll size, and revenue level. Clients never receive a surprise penalty notice. We flag deadlines in advance and confirm payments are made on time.
Business Tax Preparation and Filing Support
Focus CPA Group prepares and files all entity-level returns: Schedule C, Form 1065, Form 1120-S, Form 1120, Form 568, and all California FTB equivalents. We also handle quarterly payroll tax filings (Form 941, DE 9, DE 9C), annual Form 940, W-2 preparation, and 1099-NEC filing.
Ongoing Compliance Monitoring
Focus CPA Group monitors IRS and FTB rule changes throughout the year. When California adjusts its LLC fee thresholds or the IRS updates deposit schedules, clients are notified before the change affects them. This is the difference between a corporate tax planning strategy firm and a once-a-year tax preparer.
Never Miss a Critical California Tax Deadline Again
California’s 2026 small business tax due dates system is layered: federal IRS deadlines, California FTB deadlines, EDD payroll deadlines, and CDTFA sales tax deadlines all run on independent calendars.
Focus CPA Group is the right partner for California small businesses that want to stay ahead of every deadline, not catch up after missing one. With 20+ years of California-specific tax experience, a full team covering bookkeeping, payroll, tax planning, FTB compliance, IRS representation, and CFO-level advisory, our firm gives you a complete compliance system.
Contact Focus CPA Group today to schedule your free consultation.
FAQs
The four most critical small business tax due dates in California are: January 31 (W-2s/1099s), March 17 (S-Corp/Partnership returns), April 15 (LLC franchise tax, estimated Q1, C-Corp return), and September 15 (extended S-Corp/Partnership returns).
The California LLC tax deadline for April is April 15, 2026. Calendar-year LLCs must pay the $800 minimum franchise tax via FTB Form 3522 by that date, even with an extension filed.
IRS filing dates 2026: March 17 for S-Corps and partnerships, April 15 for C-Corps, sole proprietors, and Q1 estimated taxes, June 16 for Q2 estimated taxes, September 15 for Q3 estimated taxes.
Yes. Every California LLC pays $800 annually to the FTB, regardless of profit. The only exception is LLCs formed in 2021 or later, which received a first-year waiver under AB 85.
Quarterly estimated tax payments California business deadlines are April 15, June 16, September 15, 2026, and January 15, 2027. California's Q1 requires 30% of annual estimated liability, not 25%.
The IRS charges 5% per month on unpaid tax (up to 25%) for late filing, plus 0.5% per month for late payment. California FTB adds its own 5% late-file penalty and 0.5% monthly interest, compounding separately.
Yes. California grants an automatic six-month extension without a form if you pay 100% of the tax owed by the original deadline. If you owe tax, file FTB Form 3539 with payment to avoid penalties.
A California tax planning for small businesses CPA tracks every IRS and FTB deadline, sets up quarterly estimated payment schedules, prepares all entity returns, and monitors rule changes before they affect your filing obligations.
