Updated for 2026 · Federal and California · Last checked August 15, 2026

Every California Small Business Tax Deadline in 2026 - and Which Ones Are Actually Yours

Most deadline lists hand you forty dates and leave you to find your four. This one is sorted by what you file – an 1120-S, a 1065, or a Schedule C – and every date says which tax year it settles. Federal and California, side by side.

Compiled and kept current by Amid Kobakival, CTEC-registered tax preparer at TrueArc Tax and Financial Services in Woodland Hills, California.

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The dates

California small business tax deadlines 2026, by date

Sorted by date rather than by form or agency. Every row says who it applies to and which tax year it settles - most of what falls due in 2026 calendar year settles 2025 tax year, while the estimates you pay during 2026 belong to 2026.

You file a Schedule C. Sole proprietor, or a single-member LLC that never elected anything. April 15 and October 15, four estimates a year, plus the $800 if there is an LLC.

You file an 1120-S. An S corp, or an LLC taxed as one. March 16 and September 15 - five months earlier than most articles quote - plus payroll, plus your own 1040 in April and October.

You file a 1065. A partnership, or a multi-member LLC. Same March 16, then September 15 federally, but California allows Form 565 or 568 to October 15.

January to March 2026

January to March 2026
Date	What is due	Who it applies to	Tax year
Thu, January 15, 2026	Fourth estimated payment - federal, and the final 30% of the California year	Sole proprietors, single-member LLC owners, S corp shareholders, partners	2025
Mon, February 2, 2026January 31 falls on a Saturday	1099-NEC to every contractor and to the IRS; W-2 to every employee and to the SSA	Anyone who paid a contractor or ran payroll during 2025	2025
Mon, March 16, 2026March 15 falls on a Sunday	Form 1120-S and Form 1065 federally; California Forms 100S and 565/568 alongside them; Schedule K-1 out to every owner	S corps, partnerships, multi-member LLCs	2025
Mon, March 16, 2026	Form 2553, to elect S corp treatment effective for the whole of 2026	Anyone converting this year	2026

April to June 2026

April to June 2026
Date	What is due	Who it applies to	Tax year
Wed, April 15, 2026	Form 1040 and California Form 540; Form 1120 and California Form 100 for C corps; Form 568 for single-member LLCs	Individuals, sole proprietors, single-member LLCs, C corps	2025
Wed, April 15, 2026	Form 3522 - the $800 California annual LLC tax	Every California LLC, whether or not it earned anything	2026
Wed, April 15, 2026	First estimated payment - federal, and 30% of the California year	Sole proprietors, S corp shareholders, partners	2026
Wed, April 15, 2026	Last day to fund a 2025 IRA or HSA	Individuals	2025
Mon, June 15, 2026	Second estimated payment - federal, and 40% of the California year, the largest single California installment	Sole proprietors, S corp shareholders, partners	2026
Mon, June 15, 2026	Form 3536 - the California LLC fee, prepaid on estimated gross receipts	LLCs expecting $250,000 or more in receipts	2026

July to September 2026

July to September 2026
Date	What is due	Who it applies to	Tax year
Tue, September 15, 2026	Form 1120-S and Form 1065 federally, and California Form 100S, for anyone who extended in March. Federally this is the real deadline for an S corp or a partnership, not October.	S corps, partnerships, multi-member LLCs	2025
Tue, September 15, 2026	Third federal estimated payment. California collects nothing in September - its schedule runs 30 / 40 / 0 / 30, not four equal installments	Sole proprietors, S corp shareholders, partners	2026

October 2026 to February 2027

October 2026 to February 2027
Date	What is due	Who it applies to	Tax year
Thu, October 15, 2026	Form 1040 and California Form 540 for anyone who extended in April; California Forms 565 and 568 for extended partnerships and LLCs, on California's seven-month extension; federal Form 1120 for extended C corps	Individuals, sole proprietors, LLCs, partnerships, C corps	2025
Mon, November 16, 2026November 15 falls on a Sunday	California Form 100 for extended calendar-year C corporations - California's corporate extension runs seven months, the federal one six	C corps	2025
Thu, December 31, 2026	Equipment has to be in service, not merely ordered and paid for; the year's S corp payroll has to have actually run; a Solo 401(k) has to exist rather than be intended	Anyone with something to time	2026
Fri, January 15, 2027	Fourth estimated payment - federal, and the final 30% of the California year	Sole proprietors, S corp shareholders, partners	2026
Mon, February 1, 2027January 31 falls on a Sunday	1099s and W-2s for everything paid during 2026	Anyone who paid a contractor or ran payroll during 2026	2026
No fixed date	Statement of Information - every year for corporations, every two years for LLCs, due by the end of your registration anniversary month	Every California LLC and corporation	n/a

An extension moves the date the paperwork is due. It has never moved the date the money is due. Whatever you owe for 2025 is payable in March or April whether the return is finished or not.

Dates and figures on this page are taken from the IRS instructions for the forms named, the Franchise Tax Board's published due dates, FTB Publication 1001 and FTB Publication 3556, and the 2026 inflation-adjusted figures in Rev. Proc. 2025-32. Last checked August 15, 2026. If you find something here that has moved, tell us and it gets fixed the same week.

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The number nobody warns you about

The California LLC franchise tax: what the $800 actually is

It is not a tax on your profit. It is the price of the entity existing, and California charges it whether the entity earned anything or not.

The $800 minimum

What it is: The annual franchise tax, owed by every LLC and corporation doing business in California, paid on Form 3522 by April 15.
What it costs: $800 for every taxable year, not every profitable one. The first-year exemption expired at the end of 2023. SB 122 cuts it to $400 for a first taxable year beginning in 2027 through 2029.

The LLC gross receipts fee

What it is: A second and separate charge, stepped on California receipts rather than profit, prepaid on Form 3536 by June 15.
What it costs: $900 at $250,000 of receipts, rising in steps to $11,790. Underpay the prepayment and there is a 10% penalty on the shortfall.

The S corp rate

What it is: An LLC or corporation that elected S corp treatment pays on net income instead of receipts.
What it costs: 1.5% of net income, with the same $800 floor. No gross receipts fee at all.

The C corp rate

What it is: A C corporation pays the corporate franchise rate on net income.
What it costs: 8.84%, with the same $800 floor.

Which of those costs you least flips with your profit and your receipts separately, which is what the entity selection calculator is for. Left unpaid long enough, an unfiled return or an unpaid $800 ends with the Franchise Tax Board suspending the entity, and a suspended LLC cannot legally operate or enforce its own contracts. Getting it back takes a revivor

What moved this year

Small business tax changes for 2026, and the ones California didn't adopt

Most of what changed for 2026 is federal, and almost none of it reaches your California return. The gap between the two is wider this year than it has been in years.

Federal - what moved

The 1099 threshold triples. $600 to $2,000 for payments made during 2026. It changes who you send forms to, not what you can deduct.
1099-K returns to the old threshold. $20,000 and 200 transactions. A form you do not receive is still income you have to report.
Bonus depreciation is back at 100%, permanently, for property acquired after January 19, 2025. December equipment timing is a real decision again.
The Social Security wage base rises to $184,500. Medicare has no ceiling, and neither does the additional 0.9%.

California - what didn't

No qualified business income deduction. California does not conform to section 199A, so roughly a third of the federal benefit disappears on every California return.
Section 179 capped at $25,000, against a federal cap of $2,560,000.
No bonus depreciation at all. Not reduced: none. You carry a separate California depreciation schedule for as long as you own the asset.
The $800 minimum and the gross receipts fee are unchanged, and neither is indexed.

The consequence is that your California taxable income is higher than your federal, sometimes by a great deal, and a federal-only calculator will tell a California owner the wrong number with total confidence. The 2026 constants behind our own tools are listed on the entity wizard and the deduction finder.

The standard mileage rate moved twice this year: 72.5 cents a business mile through June 30, 2026 and 76 cents from July 1. Business miles have to be counted in two halves for 2026.

What to do when you have already missed a California tax deadline

Before anything else: pay what you can, and file even if you cannot pay. Federally the penalty for filing late is ten times the penalty for paying late - 5% of the balance a month against 0.5%.

What each kind of miss actually costs

A late 1120-S or 1065. Charged per owner, per month, even on a return with a zero balance.
A missed quarterly estimate. Interest from the date it was due, stopping the day the money arrives.
A late or underpaid Form 3536. A 10% penalty on the shortfall, charged on receipts, so it lands in loss years too.
A missed S corp election. Frequently not fatal - relief under Rev. Proc. 2013-30 is requested with the return.
An unfiled year, or an unpaid $800. Eventually the Franchise Tax Board suspends the entity, and a bank or a buyer finds out first.
Several of the above at once. The ordinary case. Books first, then the oldest open year, then the elections.

Behind on quarterly estimates. How the quarters get worked

The S corp election window has passed. Late S corp elections in California

The books are too far behind to file anything. Catch-up bookkeeping

The entity has been suspended by the FTB. Business setup and entity work

None of this gets cheaper by waiting, and a good share of the work here arrives this way. Fifteen minutes is enough to find out which of the six above you are in and what it would cost as one flat number. Book a free 15-minute consultation

The judgment call, not the formula

The S corp reasonable salary question, and why no percentage answers it

The ratios you have been given - sixty-forty, fifty-fifty, a third - appear in no statute and no published IRS position. What gets weighed is comparability: what your work would cost to buy from somebody else.

What actually gets weighed

Your training and experience, and what they are worth in your field
What you actually do, and for how many hours
What the business pays non-owners for comparable work
What comparable businesses pay for comparable services
Whether a compensation agreement exists, and whether anyone followed it

Set it too low and the distributions get recharacterized as wages, with payroll tax and penalties on top. There is also a California wrinkle a national calculator misses: federally, a dollar moved into salary is a dollar off the qualified business income deduction, and California gives no such deduction at all. What holds up is a short dated note saying what you looked at to set the number.

The salary dial on the entity wizard shows what each dollar of payroll saving costs you in deduction, and where the defensible band sits. S corp tax preparation in California

Longer pieces

When a date needs more than a row

A few of these dates need an argument rather than a row. Those get a piece of their own.

01Extensions and penaltiesAbout 10 minutes

California's October 15 extension deadline: what it moves, and what it doesn't

Published August 19, 2025 · Last checked August 31, 2026

October 15 is an extension to file, not an extension to pay - and for an S corp or a partnership it is not the date at all.

Read the full piece

Deadline questions, answered straight

If I file a federal extension, do I need to file anything with California?

Usually not. California grants its extension automatically and does not require a separate request – if you owe nothing, there is nothing to send. What California does still want is the money: the automatic extension covers filing, not payment, so a balance is due on the original date regardless of what you filed federally. The mechanics, at length →

My S corp return is on extension - is that October 15 too?

No, and this is the most expensive misunderstanding on this page. A calendar-year S corp or partnership is due in March and extends to September 15 federally. October 15 is the extended date for individual returns, which includes sole proprietors and single-member LLCs, because those file on a personal return. If you own an S corp you have both: the 1120-S in September, and your own 1040 in October. One California difference: California allows a partnership or a multi-member LLC seven months rather than six, so Form 565 or Form 568 does run to October 15 even though the federal 1065 was due in September.

Do I still owe the $800 if my LLC didn't make any money?

Yes. The $800 is a franchise tax on the entity existing, not a tax on profit, and it is owed for every taxable year an LLC is registered in California or doing business here, loss years included. The first-year exemption that used to cover new entities expired on December 31, 2023 and has not come back, so an LLC formed this year owes it this year. It is due on Form 3522 by April 15. SB 122 cuts the first-year amount to $400 for an LLC, LP or LLP whose first taxable year begins in 2027 through 2029, so a 2027 formation pays half what a 2026 formation pays in year one. It does not reach an LLC that elects S corp treatment, because that is classified as a corporation. What the $800 is, and the second fee alongside it →

What actually happens if I miss a California tax deadline?

It depends which one, and the range is wider than most people assume. A late 1120-S or 1065 is charged per owner per month even with no tax due. A missed quarterly estimate accrues interest from the date it was owed rather than a flat penalty. An underpaid June LLC-fee prepayment carries a 10% penalty on the shortfall. And an unfiled year or unpaid $800, left long enough, ends in the Franchise Tax Board suspending the entity. Most of it is fixable, and the order you fix it in matters. What each miss costs, and the order it gets unwound →

What changed for small business taxes in 2026?

Federally: the 1099-NEC reporting threshold rises from $600 to $2,000 for payments made in 2026, 1099-K reporting returns to $20,000 and 200 transactions, 100% bonus depreciation is permanent, and the qualified business income deduction is permanent with a wider phase-in for service businesses. In California: almost none of it applies. The state still gives no qualified business income deduction, still caps section 179 at $25,000, still allows no bonus depreciation, and still charges the same $800. The practical result is that your California taxable income is higher than your federal. The full list, both sides →

How much does an S corp owner have to pay themselves?

Reasonable compensation for the work actually performed – which is a comparability test, not a percentage. The ratios you have heard (60/40, 50/50) appear in no statute, regulation or published IRS position. What gets weighed is your training and experience, what you actually do and for how many hours, what the business pays non-owners for similar work, what comparable businesses pay, and whether distributions and salary track each other sensibly. There is also a California wrinkle: federally, every dollar moved into salary reduces the income the 20% qualified business income deduction is computed on, so part of the payroll-tax saving is given back – and California has no such deduction, so that offset does not exist on the California return. What holds up, and what a national calculator misses →

A calendar tells you when. It does not tell you what to do about it.

Bring last year's return, or a rough figure for this year's income. In fifteen minutes you will know which of these dates are yours, what the next one costs you, and what working together would run as a single flat number.

Or call (818) 297-4579 · email contact@truearctax.com

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