How to fill out CA Form 100 (corporation), line by line

• Start with the filing route, due date, and Form 100 basics

• Schedule Q: answer the questions that can change your filing path

• Income, state adjustments, and California net income (lines 1-22)

• Tax, credits, payments, use tax, and your final result (lines 23-45)

• Embedded schedules, attachments, and signing the return

Start with the filing route, due date, and Form 100 basics

Use Form 100 for a corporation and other entities treated as corporations for California purposes, including an LLC or partnership that elected federal corporate treatment. Do not begin this return if the corporation currently files on a water's-edge basis: the FTB directs those filers to Form 100W. An S corporation uses Form 100S instead. To correct an already filed Form 100, use the current Form 100X rather than changing the original return.

Before you enter the header

1. Use the 2025 form for calendar year 2025 or a fiscal year beginning in 2025.

2. For a calendar-year return, leave the beginning and ending date area blank. Enter dates only for a fiscal-year or short-period return.

3. Enter the legal name filed with the California Secretary of State, the FEIN, California corporation number, and SOS file number where applicable.

4. Round cents to the nearest whole dollar unless an instruction specifically says otherwise. A short-period filer also writes “short year” in the top margin.

For a domestic corporation’s first California return, the fiscal-year beginning date must be its incorporation date. The header establishes both the legal taxpayer and the period covered by every amount that follows. Gather the federal return and supporting schedules if applicable, payment records, and required California schedules or attachments before entering financial lines.

• government form instructions

Schedule Q: answer the questions that can change your filing path

Schedule Q is not just background information. Its answers can require another filing, identify a combined-report path, or establish the source for a main-return line. Complete all applicable questions, including Questions D through DD, from the corporation's records and supporting filings.

Final returns, combined reports, and California real-property changes

For Question A, select the applicable final-return status for a dissolution, surrender, merger or reorganization, IRC Section 338 sale, or QSub election. For a dissolution, withdrawal, or merger, use the date filed or to be filed with the California Secretary of State. Stopping business alone does not necessarily end minimum franchise-tax exposure: a domestic or qualified corporation remains subject to it while it exists until the appropriate SOS dissolution, withdrawal, or surrender documents are filed.

Schedule Q answers with a separate next step

For Question B1, a yes answer means complete the related combined-report questions; a no answer means skip B2 and B3 and continue to B4. A combined unitary group using one return must show separate-corporation data as well as group totals. The combined tax on line 23 includes at least the applicable minimum franchise tax for each group corporation subject to franchise tax.

Business profile and specialized entity questions

Question F cannot be blank. Choose the six-digit California principal business activity code for the specific industry group producing the greatest percentage of California total receipts, then describe the activity and principal product or service. The California code can differ from the federal code. Question M requires federal Form 8886 for each reportable transaction when applicable; Question W is yes only when the Form 100 entity is an LLC or LP classified as a corporation for federal purposes. If Question CC is yes, an SMLLC’s income, deductions, and credits may be reported on Form 100, but the SMLLC still must file Form 568. On DD3, report dollars and cents without rounding.

Income, state adjustments, and California net income (lines 1-22)

Choose the computation method before entering line 1

Lines 1 through 22 form a bridge from starting income to California net income for tax purposes. Choose the method first. Under the federal reconciliation method, line 1 starts with federal ordinary income or loss before NOL and special deductions, followed by California adjustments. Under the California computation method, Schedule F computes state ordinary income and Schedule F line 30 transfers to Form 100 line 1. A corporation using federal reconciliation may also copy federal Form 1120 Page 1 to Schedule F and transfer Schedule F line 30.

How the two income-computation methods reach line 1

State adjustments and Schedule A

1. Enter applicable California additions on lines 2 through 8; line 9 totals lines 1 through 8.

2. Enter applicable California deductions on lines 10 through 15; line 16 totals those deductions.

3. Subtract line 16 from line 9 to reach line 17, net income or loss after state adjustments.

These lines reconcile the chosen starting income with California rules. If an applicable adjustment has no specific line, use line 8 for another addition or line 15 for another deduction and attach an explanation. Schedule A column (d) supplies nondeductible tax amounts for line 2 or 3. California does not allow a deduction for California corporation franchise or income taxes or other taxes measured by net income or profits; do not include an LLC fee on those lines. Schedule D line 11 feeds line 5, while Schedule V line 7 feeds Schedule F line 2 when cost of goods sold is reported.

Line 18 through line 22: apportionment, NOLs, and disaster losses

If all corporate income is from California sources, transfer line 17 directly to line 18. If only part is California-source income, complete Schedule R first and transfer Schedule R line 35 to line 18; Question N should be answered yes. Lines 19 through 21 then record applicable NOL, EZ/TTA/LAMBRA NOL, and disaster-loss deductions. Their combined amount is subtracted from line 18 on line 22, which becomes the tax base for line 23.

Tax, credits, payments, use tax, and your final result (lines 23-45)

Lines 23-30: tax, credits, and minimum franchise tax

Line 23 applies the applicable rate to line 22: 8.84% for corporations other than banks and financial corporations, and 10.84% for banks and financial corporations. Where the minimum franchise tax applies, line 23 cannot be below it. The general minimum is $800, with a $25 minimum for domestic qualified inactive gold or quicksilver mining corporations. A corporation incorporated or qualified through the California SOS is generally not subject to minimum franchise tax for its first taxable year.

Enter up to two credits by name, code, and amount on lines 24 and 25. For more than two credits, use Schedule P (100), list two credits on lines 24 and 25, and put the remaining-credit total on line 26. Lines 24 through 26 total on line 27; line 28 subtracts credits from line 23 but cannot fall below the applicable minimum franchise tax. Schedule P also supplies applicable alternative minimum tax for line 29, and lines 28 and 29 total on line 30. For 2024 through 2026, credits generally cannot reduce tax by more than $5,000,000, subject to stated exceptions and combined-group treatment.

Lines 31-45: payments, use tax, refund, or amount due

Lines 31 through 35 collect prior-year credit, estimated payments, withholding, extension payments, and the listed refundable credit; line 36 totals them. Line 37 is different: use tax is not a total line. If line 36 exceeds line 37, subtract use tax to reach the payment balance on line 38. If use tax exceeds payments, the difference is line 39. Then compare total tax on line 30 with line 38: tax due is line 40, while an overpayment is line 41.

If there is an overpayment, line 42 is the amount credited to 2026 estimated tax and line 43 is the remaining refund. A corporation that credits an overpayment forward cannot later ask to apply it to the prior year. For direct deposit, complete routing number, account type, and account number on lines 43a-43c; do not attach a voided check or deposit slip. If Schedule J applies, revise line 40 or 41 by Schedule J line 6 and label the affected line “Schedule J.” If FTB 5806 Exception B or C was used, attach that form after the schedules and federal return and check line 44b.

Embedded schedules, attachments, and signing the return

Schedules that feed another Form 100 line

Direct schedule-to-return transfers

Schedule V calculates cost of goods sold by adding beginning inventory, purchases, labor, applicable IRC Section 263A costs, and other costs, then subtracting ending inventory. State the inventory valuation method; explain any change in quantities, costs, or valuations, and attach federal Form 970 when LIFO was adopted for goods during the year. Schedule D keeps short-term and long-term gains and losses separate before its line 11 result moves to the state-adjustment flow. California taxes capital gains at the same rate as other income and does not allow a three-year capital-loss carryback.

Financial schedules and signature area

Schedules L, M-1, and M-2 are not required when both total receipts for the year and year-end total assets are under $250,000, although the information must be available if requested. Schedule L reports beginning- and end-of-year balance-sheet amounts; M-1 reconciles book income or loss to return income or loss; M-2 analyzes unappropriated retained earnings. A corporation with assets of at least $10 million but less than $50 million must complete California Schedule M-1 and attach the specified federal Schedule M-3 materials or a complete federal return.

Sources and how this page was made

This guide explains the official sources listed below in plain language. Displayed amounts, limits, percentages, and timing rules come from that material.

• Official form: 2025 Form 100 California Corporation Franchise or Income Tax Return

• Official form instructions: 2025 Corporation Tax Booklet 100 | FTB.ca.gov