California income tax is a progressive state tax administered by the Franchise Tax Board, with nine brackets running from 1% on the lowest earnings to 12.3% at the top, plus an additional 1% Mental Health Services Tax on taxable income above $1 million. Residents owe tax on all income from any source; nonresidents owe only on income sourced to California. The state’s rules start from your federal adjusted gross income but diverge in several places that can meaningfully change what you owe.
Tax Brackets and Rates for 2025
California slices your taxable income into layers. Each layer is taxed at that bracket’s rate, not your whole income. For single filers:1Franchise Tax Board. 2025 California Tax Rate Schedules
- 1% on taxable income up to $11,079
- 2% on $11,080 to $26,264
- 4% on $26,265 to $41,452
- 6% on $41,453 to $57,542
- 8% on $57,543 to $72,724
- 9.3% on $72,725 to $371,479
- 10.3% on $371,480 to $445,771
- 11.3% on $445,772 to $742,953
- 12.3% on $742,954 and above
Married couples filing jointly get wider brackets. The 1% bracket extends to $22,158, the 9.3% bracket runs up to $742,958, and the 12.3% rate begins at $1,485,907.1Franchise Tax Board. 2025 California Tax Rate Schedules
On top of these brackets, the 1% Mental Health Services Tax applies to taxable income over $1 million for every filing status, bringing the effective top marginal rate to 13.3%. Voters approved that surcharge in 2004 to fund county mental health programs.
Because the rates are marginal, a single filer with $100,000 in taxable income does not pay 9.3% on the whole amount. The effective rate on $100,000 works out to roughly 5.7%.
Who Has to File a California Return
California recognizes three categories of filers, each with a different scope of taxable income.
Full-year residents owe California tax on all income from every source worldwide, including wages earned out of state, foreign investment income, and rental property in another state. Full-year residents file Form 540.2Franchise Tax Board. 2024 FTB Publication 1031 Guidelines for Determining Resident Status
Nonresidents owe tax only on California-source income: wages for work performed in the state, rent from California property, and gain on the sale of California real estate. Nonresidents file Form 540NR.3Franchise Tax Board. Part-Year Resident and Nonresident
Part-year residents (people who moved in or out during the year) pay tax on worldwide income for the months they were a resident and on California-source income only for the rest of the year. This split calculation also uses Form 540NR.4Franchise Tax Board. 2024 Instructions for Schedule CA (540NR) California Adjustments – Nonresidents or Part-Year Residents
The FTB sets minimum income thresholds that vary by filing status, age, and dependents. A single filer under 65 with no dependents generally does not need to file unless gross income exceeds roughly $23,000. These thresholds adjust annually, so confirm the current year’s figures in the Form 540 instructions. File anyway if California tax was withheld or you qualify for refundable credits like the CalEITC, since filing is the only way to collect that money back.
What California Taxes (And What It Doesn’t)
The usual categories are taxable: wages, salaries, bonuses, interest, dividends, business profits, rental income, retirement distributions, and pass-through income from S corporations, partnerships, and trusts.
Capital gains deserve special attention. The IRS taxes long-term capital gains at preferential rates of 0%, 15%, or 20%. California does not. All capital gains are taxed as ordinary income, so a large stock sale or real estate gain can push you into the top state brackets.5Franchise Tax Board. Capital Gains and Losses
Several income types the federal government taxes are exempt in California:
- Social Security benefits are fully excluded from California taxable income, regardless of your other income.6Franchise Tax Board. Social Security Personal Income Types
- Unemployment compensation is nontaxable at the state level. If it was included in your federal AGI, subtract it on Schedule CA.7Franchise Tax Board. Unemployment
- Interest from U.S. Treasury bonds, notes, and bills is exempt. This covers direct Treasury holdings and Treasury-only money market funds. Interest from mortgage-backed securities issued by federal agencies like Ginnie Mae does not automatically qualify.
- Active-duty military pay for California-domiciled servicemembers stationed outside the state on permanent change of station orders is not treated as California-source income and escapes state tax during that assignment.8Franchise Tax Board. Military
Standard Deduction and Personal Exemption Credit
California’s standard deduction for the 2025 tax year is $5,706 for single or married filing separately, and $11,412 for married filing jointly, head of household, or qualifying surviving spouse.9Franchise Tax Board. Deductions The federal standard deduction for 2026 is $16,100 for single filers and $32,200 for joint filers, so more of your income is exposed to state tax than you may be used to.
California also provides a personal exemption credit (per taxpayer and per dependent) that directly reduces your tax rather than your taxable income. Because it is a flat credit, it delivers the same dollar benefit at any income level.
Where California Rules Diverge From Federal Rules
Health Savings Accounts
California does not recognize HSAs. Contributions you deducted on your federal return get added back to California income, as do any employer contributions excluded from federal wages. Interest and investment gains inside the HSA are taxable to California in the year they accrue.10Franchise Tax Board. Summary of Federal Income Tax Changes
Itemized Deductions
California did not adopt most of the federal Tax Cuts and Jobs Act changes, so some items that are gone federally still work here, and vice versa. Unreimbursed employee business expenses remain deductible on the California return, and mortgage interest can be deducted on up to $1 million in debt rather than the federal cap of $750,000.
On the other side, state income taxes paid are not deductible on your California return, so there is no state analog to the federal $10,000 SALT cap workaround at the individual level.10Franchise Tax Board. Summary of Federal Income Tax Changes
529 Plan Contributions
California offers no state deduction or credit for 529 contributions. Qualified withdrawals remain tax-free at both levels, but there is no upfront benefit for putting money in. California also does not conform to the federal rule allowing 529-to-Roth IRA rollovers; such a rollover would be included in California taxable income and could trigger an early-distribution penalty.
Credits Worth Claiming
California Earned Income Tax Credit
CalEITC is refundable, meaning it can produce a refund even if you owe no tax. It is available to working filers with earned income of $32,900 or less. Maximum credits run from $302 with no qualifying children to $2,016 with one, $3,339 with two, and $3,756 with three or more. You need at least $1 of earned income, and the credit is claimed in addition to the federal EITC.11Franchise Tax Board. Eligibility and Credit Information CalEITC
Young Child Tax Credit
If you qualify for CalEITC and have a child under age six at year-end, you can also claim the Young Child Tax Credit, worth up to $1,189 per return. It is refundable and sits on top of the CalEITC. For 2025, families with earned income up to $32,900 qualify.12Franchise Tax Board. Young Child Tax Credit
Nonrefundable Renter’s Credit
Renters with AGI at or below $53,994 (single) or $107,987 (joint, head of household, or qualifying surviving spouse) can claim $60 for single filers or $120 for joint and head-of-household filers. Small, but easy to miss.13Franchise Tax Board. Nonrefundable Renter’s Credit
Filing Deadline and Extensions
The annual filing deadline for California individual returns is April 15. The FTB grants an automatic extension to file until October 15 with no application required.14Franchise Tax Board. Due Dates Personal
The extension covers filing only. Any tax you owe is still due April 15, with penalties and interest running on anything unpaid after that date. If you are not sure of your liability, overpay by April and claim the refund when you file.
California law requires preparers who use tax preparation software to e-file your return, so most professionally prepared returns are filed electronically.15Franchise Tax Board. e-File for Individuals
Estimated Tax Payments
If you have income that is not subject to withholding (self-employment, investments, rentals), you likely need to pay quarterly estimates. The requirement starts when you expect to owe $500 or more in California tax for the year after withholding and credits, or $250 for married filing separately.16Franchise Tax Board. 2024 Instructions for Form 540-ES Estimated Tax for Individuals
Payments are due in four installments: April 15, June 15, September 15, and January 15 of the following year. The spacing is uneven; the second payment comes just two months after the first. Use Form 540-ES or pay online through the FTB’s website.
Safe harbors prevent underpayment penalties if your payments cover at least 90% of the current year’s tax or 100% of the prior year’s. If your California AGI exceeds $1 million (or $500,000 if married filing separately), the prior-year safe harbor does not apply, and you must base payments on at least 90% of the current year’s tax.
Penalties and Interest
Missing the April 15 payment deadline triggers two separate charges. The delinquent filing penalty is 5% of unpaid tax per month, up to a maximum of 25%.17Franchise Tax Board. Common Penalties and Fees Interest accrues on unpaid balances from the due date until paid; for the period through June 30, 2026, the personal income tax interest rate is 7%.18Franchise Tax Board. Interest and Estimate Penalty Rates
Underpaid estimated taxes carry a separate penalty on each short installment at an annualized rate (currently 4%), calculated day by day from the installment’s due date until the earlier of payment or the filing deadline. Catching up as soon as you spot the shortfall stops the clock.
The automatic extension to October 15 eliminates the late-filing penalty but does nothing about interest or late-payment charges. If you cannot pay in full by April 15, file on time and pay what you can; that alone stops the 5%-per-month filing penalty from compounding.