California tax forms & filing.

Things to know about filing in California

• California is a community property state. For married couples, this affects how income is allocated, how separate-property gains are treated, and how a domicile move to/from California is documented. RDPs (Registered Domestic Partners) file as a married couple for state purposes only — there is no federal RDP filing status.
• California assesses a Mental Health Services Tax surtax on taxable income above the high-income threshold, on top of the regular top marginal rate. Equity compensation events (RSU vests, ISO exercises, qualified sales) frequently push residents into this surtax.
• California's nonresident sourcing rules for stock-based compensation are nuanced: RSUs granted while a California resident remain partially California-sourced even after you leave the state, allocated by the workdays-in-California portion of the vesting period. This is the single most-misfiled item for tech employees who move out of California mid-vest.
• California does not conform to federal treatment of HSA contributions, certain depreciation rules, or some retirement account changes. Conformity is selective and lags federal law by 1–3 years on each provision.
• California has no state-level inheritance or estate tax — federal estate tax only.

California RSU sourcing for people moving out of the state

Of all the California-specific items we see, the one that's most often misfiled in DIY software is RSU sourcing after a California-to-other-state move. The rule isn't intuitive: even after you've become a resident of another state, California claims a portion of every RSU tranche that vested while you were a California resident or while it was earning toward vesting in California.

The mechanics: California allocates the income from each RSU vest by the ratio of California workdays during the vest's earning period to total workdays in that period. If a 4-year vesting grant was granted in California and vested 2 years after you moved to Texas, roughly half of each vest tranche is still California-source income for state purposes — even though you were a Texas resident on the vest date.

The same logic applies in reverse to ISOs and NSOs that span a residency change. We model this at intake using the equity-comp grant documentation, vesting schedule, and the workdays calendar — and we file the California nonresident return (Form 540NR) to capture the California-source income and pay California tax on it. Failing to file generates state notices later; California is the most aggressive state we see on cross-border equity income.

Multi-state filing patterns we see most often for California residents

California to Texas or Florida (no-tax states): The most common 'tax-motivated' move. We file a California part-year return for the year of departure and continue filing California nonresident returns for any post-move California-source income (deferred comp vests, real estate, passthrough interests). Establishing the move out of California requires documentation — domicile is not a checkbox.

California to Washington or Oregon: Tech-corridor moves. Washington has no wage income tax but a capital gains tax on high earners. Oregon has the highest top marginal rate in the country. Comparing tax outcomes pre-move is part of our intake conversation.

Bay Area resident, NYC employer: Convenience-of-employer rules on the New York side combined with California residency create a double-tax exposure that's usually but not always resolved by the California credit for taxes paid to another state. The interaction matters and is checked at intake.

Where's my refund?

The California Franchise Tax Board (FTB) runs the official refund-status tracker. You'll need your Social Security number, filing status, and exact refund amount (in some cases, the tax year and a return-amount input).

Check your California refund status →

Multi-state considerations

If you lived or worked in more than one state during the tax year, you typically file a part-year resident return in each state. If you live in one state and work in another, you usually file as a resident where you live and as a nonresident in the work state — claiming a credit on the resident return for taxes paid to the work state. Reciprocity agreements between some neighboring states change this default; we map this out at intake.

California-specific multi-state nuances are addressed in the quirks list above when they apply.

Get the current-year forms

State tax rates, brackets, and forms change every year. We point to the California Franchise Tax Board (FTB) as the authoritative source for current-year information. Form numbers above are stable; rates, deduction amounts, and credit limits are not — always verify before relying on a specific dollar amount.

Open the California Franchise Tax Board (FTB) website →