California LLC Tax Filing Due Date In 2026 + Extensions

There are numerous opportunities for Limited Liability Companies (LLCs) operating in California to grow, but they must also comply with unique state and federal tax filing requirements.

For 2026, LLCs operating in California are taxed in two different ways: 

• Income taxes

• Franchise taxes

The LLC owners pay income taxes on their individual IRS Form 1040, U.S. Individual Income Tax Return, while franchise taxes are levied against the actual LLC itself.

Use this blog to learn about filing due dates and penalties for missing them during the 2026 tax season, along with extensions for your California LLC, and how expert support can help simplify time-consuming tax responsibilities. 

California LLC Tax Due Dates (2026)

LLCs with only one owner are taxed as sole proprietorships by default, while LLCs with more than one owner are taxed as partnerships by default. In both situations, the LLC's net income or losses flow through to the small business owner’s individual tax return, known as pass-through taxation. The owner will then be taxed at a rate up to 13.3% in California, with the top individual federal tax rate being 37%.

The business structure that you operate as determines when you file taxes. 

• Single-member LLC: File by April 15, 2026.

• Multi-member LLC: File Form 568 by March 15, 2026.

• S corporation: File by March 15, 2026. 

• C corporation: File by April 15, 2026. 

If state or federal deadlines fall on weekends or holidays, the next business day applies.

California LLC Tax Extensions (2026)

If you’re a full-year resident of California, you’ll file your share of your LLC’s revenue and expenses on Form 540, which is California’s form for individual income tax returns.

If you don’t reside in California or only live there for part of the tax year, you’ll file your share of your LLC’s revenue and expenses on California’s Form 540NR for nonresident individual income tax returns.

If you need extra time, California allows an automatic six-month extension for businesses and individuals as long as you pay any tax owed to California by the original due date. No forms need to be filed to extend your tax return due date.

• September 15, 2026, for partnerships and S corporations. 

• October 15, 2026, for individuals.

The IRS has granted individuals and businesses in certain parts of California impacted by natural disasters an extension. 

Late Filing Penalties

Three types of penalties and interest can be assessed against your California LLC for failing to meet a filing deadline. These penalties include: 

1. Failure to Comply with Filing Requirements. Unless there’s a reasonable cause, a penalty will be assessed if your LLC is required to file Form 568 and fails to file the return on time (including extensions), or the LLC files Form 568 that fails to show all the necessary and up-to-date information.

2. Failure to File a Timely Return. If your LLC fails to file Form 568 on or before the extended due date, you will be assessed a penalty. 

3. Failure to Pay by the Due Date. This penalty begins at 5%. Every month (or partial month) that the amount is not paid, the penalty increases by 0.5%. 

Interest is assessed on any tax due if not paid by the original due date. Interest is also levied on specific penalties. 2026 penalty rates include: 

• $18/partner/month for missed Form 568 (max 12 months).

• 5% of unpaid tax/month for late filing (max 25%).

• 0.5% monthly late payment penalty (max 25%).

Quarterly Estimated Taxes in California (2026)

If you expect your LLC in California to owe $500 or more in state income tax annually, you must calculate and file quarterly estimated taxes.

These are the due dates for filing your LLC's quarterly estimated taxes: 

• April 15th

• June 15th 

• September 15th 

• January 15th

As with other state and federal filing deadlines, if a deadline falls on a weekend or holiday, you must file your quarterly estimated tax payments by the following business day. 

Small Business Tax Filing Exemptions in California

LLCs are pass-through entities, meaning that profits are passed through to each owner and reported on their individual tax returns. If you feel your LLC in California should be tax-exempt, similar to a non-profit, you would file Form FTB 3500 with the state of California.

Once your application is prepared and any supplemental documentation is attached, submit your materials to the California Franchise Tax Board. After reviewing your submission, the California Franchise Tax Board will determine if your LLC qualifies for this status. 

How to File LLC Taxes in California

To determine how much your LLC's franchise tax fee will be, you’ll file a “Return of Income.” Since your LLC in California may be classified for tax purposes as a partnership, a corporation, or a disregarded entity, you must file the appropriate California tax return for its classification (classification determines the tax form you'll use):

• Sole proprietorships file Form 540 or 540NR, depending on their residence. 

• Partnerships file Form 568, Limited Liability Company Return of Income (LLCs classified as partnerships should not file Form 565, Partnership Return of Income).

• General corporations file Form 100, California Corporation Franchise or Income Tax Return.

• S corporations file Form 100S, California S Corporation Franchise or Income Tax Return.

For LLCs classified as partnerships, the due date for filing Form 568 is the 15th day of the third month following the close of the taxable year. If your LLC follows the calendar year, March 15th is the filing deadline. 

If you cannot file Form 568 by the due date, you are granted an automatic seven-month extension unless your LLC in California has been suspended or forfeited. 

Key 2026 Tax Law Changes Affecting LLCs

There are federal and state-level changes that will impact your California LLC in 2026. On the federal level, the One Big Beautiful Bill Act, passed in 2025, introduced numerous tweaks and changes, including: 

• 100% bonus depreciation restored.

• SALT deduction cap raised to $40,000 for incomes < $500,000.

• IRS Form 1099-NEC, Nonemployee Compensation, threshold rises to $2,000 in 2026.

On the state level, there have been updates to payroll rules. The new salary threshold for exempt employees is $1,320 per week, which went into effect on January 1, 2025.

How 1-800Accountant Can Help

Calculating and filing your California LLC taxes accurately and on time, while building your business, is a delicate balancing act. If an error is made or a tax deadline is missed, it can invite penalties and disrupt your operations. No one needs those headaches, which is why many California LLCs trust 1-800Accountant, America’s leading virtual accounting firm, as their full-service financial partner.

Whether it's business tax preparation, quarterly estimated taxes, payroll, bookkeeping, tax advisory, or entity formation, we have the affordable, tax-deductible solutions you need to ensure your California LLC remains tax-compliant. 

Schedule a Free 30-Minute Consultation + File Your Business Taxes Online Today!