California Form 100 — Corporation Franchise or Income Tax Return 2025-2026

Get the blank Form 100 (PDF)  ·  Checked line by line against the official California form, last verified October 14, 2026  ·  How we verify

What is Form 100?

California taxes corporations in two ways. The franchise tax applies to corporations incorporated or qualified in the state or doing business in it, and is measured by the year’s income. The income tax applies to corporations that earn California-source income without doing business here. Both use the same rates and the same Form 100.

S corporations file Form 100S, corporations electing the water’s-edge method file Form 100W, and LLCs or partnerships that are classified as partnerships file Form 568 or Form 565 instead.

Who Must File Form 100?

File Form 100 if you are a corporation (including an LLC that elected to be taxed as a corporation) that is incorporated or organized in California, qualified or registered to do business here, or doing business in California, and also if you earn California-source income as a corporation without doing business here.

“Doing business” is broader than many expect. For 2025 a corporation is doing business if it actively engages in any transaction for profit in California, is organized or commercially domiciled here, or exceeds one of the thresholds: California sales over the lesser of $757,070 or 25% of total sales, California property over the lesser of $75,707 or 25% of total property, or California payroll over the lesser of $75,707 or 25% of total compensation. Even an isolated transaction may be enough.

Other filers of Form 100 include banks and financial corporations, REITs, RICs, REMICs, publicly traded partnerships that are not eligible for the federal election, and certain exempt homeowners’ associations and political organizations with taxable income over $100.

Special cases: corporations that meet Public Law 86-272 protection and file no combined report do not include their income on line 18 (write “PL 86-272” at the top), but they still owe the minimum franchise tax if they are doing business in, incorporated in or qualified in California.

How to File Form 100

• Pick the right return: Form 100, or Form 100S for an S corporation, or Form 100W for water’s-edge filers.
• Choose a computation method. Either the federal reconciliation method (start with federal Form 1120 income on line 1 and make state adjustments on lines 2–16) or Schedule F, the California computation method, if there is no federal return or separate state records.
• Apportion if needed. If only part of the income comes from California, complete Schedule R and carry its result to line 18, then answer “Yes” to Question N.
• Assemble in order: Form 100, Schedule R if required, supporting schedules, a copy of the federal return if required, and FTB 5806 if required. Do not staple.
• Pay. Corporations over the EFT thresholds must pay electronically. Others can mail a check payable to the Franchise Tax Board, with the California corporation number and “2025 Form 100” on it, or use FTB 3586 with an e-filed return.
• File electronically if you can. Business e-file is available for Form 100, 100W, 100S and 100X.

When Is Form 100 Due?

The return is due on or before the 15th day of the 4th month after the close of the taxable year, which is April 15 for a calendar-year corporation. If that date is a weekend or holiday, it moves to the next business day. A corporation that cannot file by then may file on or before the 15th day of the 11th month without a written extension request, except entities suspended on or after the original due date. The extension is only for filing. The full tax must be paid by the original due date; if tax is owed, send FTB 3539 with the payment, or pay electronically. Farmers’ cooperative associations file by the 15th day of the 9th month.

Where to Mail Form 100

Return with payment: Franchise Tax Board, PO Box 942857, Sacramento CA 94257-0501. Return without payment, refund return, or return paid electronically: PO Box 942857, Sacramento CA 94257-0500. E-filed return with FTB 3586: PO Box 942857, Sacramento CA 94257-0531. Private delivery services use FRANCHISE TAX BOARD, SACRAMENTO CA 95827, never a PO box.

How to Complete Form 100 Line by Line

Top of the Return and Line 1 — Federal Reconciliation or Schedule F

Use black or blue ink, print the name and address in capital letters and round to whole dollars. A first-year domestic corporation’s fiscal year begins on the date of incorporation. Line 1 is federal ordinary income (loss) from trade or business before any NOL and special deductions when you use the federal reconciliation method, or the amount from Schedule F, line 30, if you compute income under California law. Under the reconciliation method, attach the federal return.

Lines 2–16 — State Adjustments to Income

These lines convert federal income to California income: additions such as

Line 15 also removes exempt interest and certain California exclusions, such as wildfire settlements, for a corporation that included them as federal income.

Lines 17–18 — Net Income After Adjustments and for State Purposes

A net loss on line 18 requires the 2025 form FTB 3805Q.

Lines 19–21 — NOL, EZ/TTA/LAMBRA and Disaster Loss Deductions

Lines 23–29 — Tax, Credits, Balance and AMT

Lines 32–37 — Estimated Tax, Withholding and Use Tax

Lines 40–44 — Tax Due or Overpayment, Credit, Refund and Penalties

Common Mistakes to Avoid

• Skipping the minimum franchise tax for an inactive or loss-making corporation after its first year.
• Treating the extension as a payment extension. Tax is due on the original date; use FTB 3539 or pay electronically.
• Missing the electronic payment rule. Over $20,000 for an estimated or extension payment, or $80,000 total liability, triggers mandatory electronic payment and a 10% penalty if ignored.
• Claiming an NOL carryover at $1,000,000 or more of taxable income in 2024–2026. The deduction is suspended.
• Forgetting Schedule R when only part of the income is from California.
• Filing Form 100 for an S corporation. That entity files Form 100S.
• Reporting use tax on the return when the business must report it to CDTFA.

Frequently Asked Questions

What is the California corporate tax rate? 8.84% of net income, and 10.84% for banks and financial corporations.

What is the minimum franchise tax? $800 for most corporations subject to the franchise tax, including inactive ones; it does not apply in the first taxable year of a corporation that incorporated or qualified through the Secretary of State.

When is Form 100 due? The 15th day of the 4th month after year-end; the automatic filing extension runs to the 15th day of the 11th month.

Does the extension give me more time to pay? No. The full tax is due by the original due date.

Does an LLC ever file Form 100? Yes, if the LLC elected to be taxed as a corporation.

Can I e-file Form 100? Yes. Business e-file is available for Form 100, 100W, 100S and 100X.

Final Review Before Filing

• The entity is a corporation (not an S corporation or a partnership-classified LLC).
• Line 1 uses either the federal reconciliation or Schedule F method.
• Schedule R is attached if only part of the income is from California.
• The tax on line 23 is at least the minimum franchise tax when it applies.
• The NOL and credit limits for 2024–2026 are applied.
• Estimated tax, extension and withholding payments are on lines 32 and 33.
• Payment is electronic if the EFT thresholds were crossed.

General information from the official form and its instructions, not advice for your circumstances. See the full disclaimer.