California State Income Tax: Brackets and Paycheck Withholding
California runs progressive brackets plus a mental health surcharge on very high income, and withholds through Form DE 4. What comes out of a California paycheck and why.
California has one of the more complex state income tax systems in the country, and a California pay stub reflects that. Alongside federal tax and FICA, you will usually see state income tax and a state disability insurance deduction, each calculated under its own rules.
How the Brackets Work
California applies graduated rates across a series of brackets, administered by the Franchise Tax Board. The rates climb with taxable income and the bracket thresholds are adjusted periodically, so the figures to use are the ones published for the tax year you are filing, not a remembered rate.
Above $1 million of taxable income an additional 1% mental health services tax applies. It affects very few filers but it is a genuine part of the schedule.
Withholding Runs on Form DE 4
California does not rely on your federal Form W-4. The state has its own Employee's Withholding Allowance Certificate, Form DE 4, and payroll uses it with the state's withholding schedules. If you completed a federal W-4 and never filed a DE 4, your state withholding is being calculated on a default basis that may not match your situation.
This is the single most common reason a California employee owes state tax at filing time despite having withholding on every stub.
The SDI Line
California withholds State Disability Insurance from employee wages. It is not income tax; it funds disability benefits and paid family leave. The rate is set annually, so check the current figure rather than carrying one forward.
I work through the bracket mechanics, the DE 4 and how residency affects what California can tax in my guide to California state income tax for Online Paystub.
Which Form You File
Full-year residents file Form 540. Part-year residents and nonresidents with California-source income file Form 540NR, which allocates income between the period of residency and income sourced to the state afterwards. If you moved into or out of California during the year, that distinction decides most of your return.