Deadlines for filing small business taxes in California
6 min read
August 10, 2023 • Block Advisors
California dominates the top spot for the number of small businesses according to the US Small Business Administration, with 4.2 million small businesses as of 2022. That’s 99.8% of all California businesses! For this state’s burgeoning community of small business owners, tax season is a pivotal period that requires careful navigation through a maze of California tax deadlines. If you are a small business owner wondering “When are taxes due in California?” look no further. Below, we’ll cover important business tax deadlines to help you stay on top of this crucial activity.

Note on the impact of the California Winter Storm Disaster
In 2023, California state individual income tax returns were originally due April 18. California quarterly estimated tax payments were originally due on April 18 (Q1), June 15 (Q2), September 15, (Q3), and January 16 (Q4). Business returns were generally due either March 15 or April 18.
However, residents and businesses in most counties across the state were given an automatic extension — until October 16 — to file both their federal and state returns as part of the winter storm disaster tax relief measures. The California tax deadline change applies to both annual tax returns and quarterly estimated tax payments for Q1, Q2, and Q3, and Q4. Any California tax payments due March 18, 2023 also qualify for the extension. This Emergency Tax Relief extension was announced by the State of California on March 10. Relief for Modoc and Shasta counties applies through August 15, 2023.
Each year you should review the small business tax deadline to ensure you’re aware of any changes. For Lassen county, disaster postponements did not apply. For most small businesses located in areas not impacted by the disaster, business income tax deadlines for 2023 in California are on April 18. Multi-member LLCs, S corporations, and Partnerships, however, must file tax returns by March 15.
When are taxes due in California?
When it comes to tax compliance, small business owners must know when taxes are due in California. In this section, we’ll outline the key deadlines, including the California business tax filing deadline for 2023, that every California entrepreneur should mark on their calendar to ensure a seamless tax filing process.
From income tax deadlines to quarterly tax deadlines to employment tax deadlines for small businesses, staying informed about these crucial dates will help small businesses stay on track and avoid any last-minute rush or penalties. Keep reading to ensure you are aware of federal and California business tax filing deadlines.
Income tax deadlines
Most small businesses need to file federal income taxes annually. These taxes are based on the revenue your company earns each year. The form you need for your income tax return depends on your business structure. You may use one of the following Internal Revenue Services (IRS) forms:
- Sole Proprietors or LLCs – IRS Form 1040 using a Schedule C
- C Corporations – IRS Form 1120
- S Corporations – IRS Form 1120S
- Partnerships – IRS Form 1065
For many small businesses, including Sole Proprietorships, Single-Member LLCs, and C Corporations, the business tax deadline is April 18, 2023. However, keep in mind that some small businesses have an earlier tax deadline. This includes S Corporations, Multi-Member LLCs, and Partnerships. So, if this is how you’re structured, you’ll need to finish filing your return earlier – March 15, 2023. Generally, the California tax deadline for income tax aligns with the federal deadline.
If you found yourself needing additional time to file your income taxes when the California tax deadline came around, you may have filed a tax extension using IRS Form 7004. If this is the case, you have until October 16, 2023, to file your individual or corporate tax return.
Quarterly tax deadlines for small businesses
The quarterly estimated taxes you need to file also depend on your business structure. Sole proprietors, partners, and S Corporation shareholders who expect to owe more than $1,000 at tax time are generally required to make federal quarterly estimated tax payments. This recurring filing is in addition to their annual income tax filing. C Corporations who expect to owe $500 or more when filing their corporate income tax return also generally are required to make federal quarterly estimated tax payments. Read our article to learn more about federal estimated tax payments.
Some important federal quarterly tax dates for 2023 to keep in mind:
- April 18 – 1st quarter (Q1) 2023 estimated tax payment due
- June 15 –2nd quarter (Q2) 2023 estimated tax payment due
- September 15 –3rd quarter (Q3) 2023 estimated tax payment due
- January 15, 2024 – 4th quarter (Q4) 2023 estimated tax payment due
NOTE: The federal estimated tax due dates are generally April 15, June 15, September 15, and January 15. When the date falls on a weekend or holiday, the deadline is moved to the next workday. If you’re wondering about other business tax deadlines, see a more comprehensive list of all federal business tax deadlines.
Though the California tax deadline often matches the federal for estimated tax payments, some years they are slightly different. Make sure you are aware of the current year’s California tax deadlines and forms for California quarterly estimated taxes available on the California Franchise Tax Board website.
If you’re feeling unsure, a Block Advisors certified small business tax pro can help you understand which forms and deadlines you need to consider.
Employment tax deadlines
If your business has employees, you’ll need to report their wages, tips, and other compensation. To do this you use IRS Form 941 for federal purposes, filing it with your usual quarterly tax return. This form reports employer payments and FICA taxes withheld from your employees’ paychecks quarterly. On top of these, you may also need to file state forms by the California tax deadline.
Don’t confuse this with employee and contract worker-centered forms that require annual filings such as IRS Form W-3, W-2, and 1099s.
Get more help with California tax deadlines
It’s important to be aware of business tax deadlines. If keeping track of both the federal and California business tax filing deadlines has you feeling overwhelmed, we are here to help. Block Advisors certified small business tax pros are available all year long, remotely and in person, to help you nail your tax return.
Find out how you can save time and money while keeping your small business taxes on track.
