Last reviewed against the Franchise Tax Board's 2025 Form 100 booklet and 2026 Form 100-ES instructions.
How is California franchise tax calculated for a C-corp?
A corporation that is incorporated in California, qualified or registered with the California Secretary of State, or doing business in California files Form 100 and pays franchise tax. The computation has two parts:
- Tax on income. California net income (Form 100, line 22) times 8.84%. Banks and financial corporations use 10.84%. A loss produces zero tax on income, never a negative tax.
- The minimum franchise tax floor. Form 100, line 23 is "at least minimum franchise tax, if applicable": $800 for most corporations. It is a floor, not a separate charge, so you pay the larger of the two numbers, not both.
Below about $9,050 of net income, the $800 minimum is what you owe. Above it, 8.84% of income is larger. Credits reduce the tax, but never below $800.
Do you owe $800 even with a loss?
Yes, and this surprises founders more than anything else about California. The FTB's instructions say the minimum franchise tax is owed "whether the corporation is active, inactive, operates at a loss, or files a return for a short period." A pre-revenue startup with a $500,000 loss owes $800. So does a Delaware C-corp registered in California because its founders live here.
The minimum stops only when the corporation files its dissolution, withdrawal or surrender documents with the Secretary of State. Going quiet does not stop it.
How does the first-year exemption work?
A corporation that incorporates or qualifies through the California Secretary of State is not subject to the minimum franchise tax for its first taxable year. It multiplies its California net income by 8.84% instead, so a first-year corporation with a loss owes nothing, and one with $5,000 of income owes $442 rather than $800.
Three details catch people out:
- The first year is a taxable year, not twelve months. A calendar-year corporation formed in November has a first taxable year of about two months. Its second taxable year starts January 1, and the $800 is due with the first estimate that April.
- It does not apply to corporations not qualified by the Secretary of State, or to a reorganization made to avoid the minimum.
- First-year income is still taxed. The 100-ES instructions tell new corporations to base estimates on annualized current-year income to avoid a penalty.
Worked example
The calculator's defaults: a calendar-year C-corp in its third year with $50,000 of California net income for 2026.
| Step | Calculation | Result |
|---|---|---|
| Tax on income | $50,000 x 8.84% | $4,420 |
| Minimum franchise tax | not the first taxable year | $800 |
| Tax (larger of the two) | $4,420 | |
| Installment 1, April 15, 2026 | 30% | $1,326 |
| Installment 2, June 15, 2026 | 40% | $1,768 |
| Installment 3, September 15, 2026 | 0% | $0 |
| Installment 4, December 15, 2026 | 30% | $1,326 |
The 2026 Form 100 is due April 15, 2027 (November 15, 2027 with the automatic extension to file).
Change the income to a $500,000 loss and the tax drops to the $800 minimum, all of it due April 15. At $20,000 of income the tax is $1,768: 30% would be only $530.40, so the first installment is raised to $800, and the rest is spread to reach 70% by June ($437.60) and 100% by December ($530.40).
When are California estimated payments due?
Estimated tax is paid in four installments on the 15th day of the 4th, 6th, 9th and 12th months of the taxable year, at uneven percentages:
- 1st installment, 30% (April 15 for calendar-year filers), and never less than the $800 minimum.
- 2nd installment, 40% (June 15).
- 3rd installment, 0% (September 15). Nothing is required.
- 4th installment, 30% (December 15).
If the year's estimated tax does not exceed the $800 minimum, the whole amount is due with the first installment. When a due date falls on a weekend, it moves to the next business day; the calculator applies that rule, but not state holidays. Payments go through Web Pay, EFT or Form 100-ES.
Common mistakes
- Skipping the $800 because there was no revenue. The minimum applies at a loss. Unpaid, it builds penalties and interest and can lead to suspension.
- Spreading the $800 across the year. It is all due with the first installment, April 15 for a calendar-year corporation.
- Assuming the extension covers payment. The automatic extension moves the filing date to November 15, not the payment date.
- Copying the federal quarterly pattern. Federal estimates are 25% each; California's are 30/40/0/30.
- Claiming the first-year exemption twice. It covers one taxable year, which may be very short.
- Using federal taxable income as is. Form 100 starts from federal income but adds back and subtracts California differences, and multistate companies apportion income to California.
Frequently asked questions
Do I have to pay California's $800 franchise tax if my corporation lost money?
Yes. The minimum franchise tax is owed whether the corporation is active, inactive, operates at a loss, or files a short-period return. A C-corp with a $500,000 loss still owes $800, and credits cannot reduce the tax below the minimum. The only common exception is the first taxable year of a corporation that incorporated or qualified through the California Secretary of State.
How is California corporate franchise tax calculated?
California net income times 8.84% for most C-corporations (10.84% for banks and financial corporations), but never less than the $800 minimum franchise tax when it applies. The tax equals $800 until net income reaches about $9,050, the point where 8.84% of income equals $800.
Is a new corporation exempt from the $800 minimum in its first year?
A corporation that incorporates or qualifies through the California Secretary of State is not subject to the minimum franchise tax for its first taxable year. It pays 8.84% of any California net income instead, and owes the minimum from its second taxable year. The first taxable year can be only a few weeks long for a company formed late in the year.
When are California corporate estimated tax payments due?
On the 15th day of the 4th, 6th, 9th and 12th months of the taxable year: April 15, June 15, September 15 and December 15 for a calendar-year corporation. The required amounts are 30%, 40%, 0% and 30% of the year's estimated tax. If the estimated tax is no more than the $800 minimum, the whole amount is due with the first installment.
When is California Form 100 due?
The 15th day of the 4th month after the close of the taxable year, which is April 15 for calendar-year corporations. California grants an automatic 7-month extension to file, to November 15, but it does not extend the time to pay. Any unpaid tax is due by the original date.
Does this calculator work for S corporations or LLCs?
No. It covers C-corporations filing Form 100. S corporations file Form 100S and pay 1.5% of net income with the same $800 minimum. LLCs pay an $800 annual tax on form FTB 3522, plus an LLC fee once California income passes $250,000, and new LLCs no longer get a first-year exemption.
Sources
- Franchise Tax Board, 2025 Form 100 Booklet
- Franchise Tax Board, 2026 Form 100-ES Instructions
- Franchise Tax Board, Corporations
- Franchise Tax Board, Web Pay
This calculator and article are general information, not tax or legal advice. Check the current FTB instructions or a California tax professional for your situation.