Updated October 24, 2026. Quick answer: Line 31 of California Form 540 is your tax. The booklet says “To figure your tax, use one or more of the following methods and check the matching box(es) on line 31, as applicable:” The methods are the tax table, the tax rate schedules, form FTB 3800 and form FTB 3803, and which one applies depends on your line 19 taxable income and your family situation.
What this line does
The form’s line 31 reads “Tax. Check the box if from: Tax Table Tax Rate Schedule FTB 3800 FTB 3803”. It is on the page headed “Side 2 Form 540 2025”, in the part headed Tax.
The amount comes from your taxable income on line 19. Line 32 subtracts exemption credits, and the form’s line 33 says “Subtract line 32 from line 31. If less than zero, enter -0-”. For the full sequence see California Form 540 line by line.
Who it applies to
The booklet sorts filers by the amount on line 19 and by family situation. For the two table based methods the condition is the size of your taxable income: “If your taxable income on line 19 is $100,000 or less, use the tax table beginning on page 69.” or “If your taxable income on line 19 is over $100,000, use the tax rate schedule for your filing status on page 75.”
Form FTB 3800 is for a different filer, a child: “Generally, use form FTB 3800, Tax Computation for Certain Children with Unearned Income, to figure the tax on a separate Form 540 for your child who was age 18 and under or a” and the sentence continues on the next booklet page with “full-time student under age 24 on January 1, 2026, and who had more than $2,700 of unearned income.”
Form FTB 3803 is for a parent who makes an election: “If, as a parent, you elect to report your child’s interest and dividend income of more than $1,350 but less than $13,500 on your tax return, complete form FTB 3803, Parents’ Election to Report Child’s Interest and Dividends.”
What the instructions say
| Line | What the form says |
|---|---|
| Form, line 31 | “Tax. Check the box if from: Tax Table Tax Rate Schedule FTB 3800 FTB 3803” |
| Booklet, how to start | “To figure your tax, use one or more of the following methods and check the matching box(es) on line 31, as applicable:” |
| Tax Table | “If your taxable income on line 19 is $100,000 or less, use the tax table beginning on page 69.” “Use the correct filing status column in the tax table.” |
| Tax Rate Schedules | “If your taxable income on line 19 is over $100,000, use the tax rate schedule for your filing status on page 75.” |
| FTB 3800, first part | “Generally, use form FTB 3800, Tax Computation for Certain Children with Unearned Income, to figure the tax on a separate Form 540 for your child who was age 18 and under or a” |
| FTB 3800, next page | “full-time student under age 24 on January 1, 2026, and who had more than $2,700 of unearned income. Attach form FTB 3800 to the child’s Form 540.” |
| FTB 3803, election | “If, as a parent, you elect to report your child’s interest and dividend income of more than $1,350 but less than $13,500 on your tax return, complete form FTB 3803, Parents’ Election to Report Child’s Interest and Dividends.” |
| FTB 3803, one form per child | “File a separate form FTB 3803 for each child whose income you elect to include on your Form 540.” |
| FTB 3803, adding the tax | “Add the amount of tax, if any, from each form FTB 3803, line 9, to the amount of your tax from the tax table or tax rate schedules and enter the result on Form 540, line 31.” |
| FTB 3803, attachment | “Attach form(s) FTB 3803 to your tax return.” |
| Accuracy | “To prevent possible delays in processing your tax return or refund, enter the correct tax amount on this line.” |
| Online calculator | “To automatically figure your tax or to verify your tax calculation, use our online tax calculator.” |
The figures the form prints
Several dollar figures sit inside running sentences. The line 19 cutoff is in “If your taxable income on line 19 is $100,000 or less, use the tax table beginning on page 69.” and “If your taxable income on line 19 is over $100,000, use the tax rate schedule for your filing status on page 75.” The child’s unearned income figure is in “full-time student under age 24 on January 1, 2026, and who had more than $2,700 of unearned income.” The election range is in “If, as a parent, you elect to report your child’s interest and dividend income of more than $1,350 but less than $13,500 on your tax return”.
The tax table (booklet page 69 on) and the tax rate schedules (booklet page 75) are printed tables with columns by filing status. This page does not read amounts or rates from them; use your own booklet or the online calculator.
Where the result goes next
The line 31 amount goes forward through the credit lines. Line 33 reads “Subtract line 32 from line 31. If less than zero, enter -0-” and line 35 reads “Add line 33 and line 34.”. Exemption credits are covered on California Form 540 line 32, and the state overview is on California retirement taxes. If you also want the federal comparison see Form 1040 line 16.
Edition and line numbers
This page reads the California 540 Forms and Instructions, 2025 Personal Income Tax Booklet, and Form 540, California Resident Income Tax Return (2025), for tax year 2025, the current file the Franchise Tax Board served on 2026-10-24. Check the edition printed on your own form and use that edition’s line numbers.
Common mistakes
- Reaching for the tax table with a large line 19 amount. The booklet says “If your taxable income on line 19 is over $100,000, use the tax rate schedule for your filing status on page 75.”
- Not adding a parent’s election tax to the line 31 amount. The booklet says “Add the amount of tax, if any, from each form FTB 3803, line 9, to the amount of your tax from the tax table or tax rate schedules and enter the result on Form 540, line 31.”
- Not checking the matching box. The booklet says “check the matching box(es) on line 31, as applicable:”
Related: California retirement taxes, California tax brackets, Form 1040 line 16, and whether California taxes pensions.
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Answer againSources
- California 540 Forms and Instructions, 2025 Personal Income Tax Booklet, Franchise Tax Board: www.ftb.ca.gov
- Form 540, California Resident Income Tax Return (2025), Franchise Tax Board: www.ftb.ca.gov
- Related official page (not quoted): Franchise Tax Board, 2025 Personal Income Tax Booklet page: www.ftb.ca.gov
Read from the state revenue documents linked above on October 24, 2026. General information, not tax advice. Your own facts decide the outcome, and a preparer or the state revenue department is the right place to confirm anything consequential.