About this California + federal tax calculator
This free calculator estimates your combined California state and federal income tax for the 2025 tax year. Unlike a simple bracket lookup, it handles the income types that actually drive a real tax bill in California — wages, long- and short-term capital gains, qualified dividends, pensions, Social Security, traditional 401(k)/IRA withdrawals, Roth distributions, and more — and shows how each is taxed differently at the federal and state levels. It also compares the standard deduction against itemizing, applies the Net Investment Income Tax and early-withdrawal penalties where relevant, and tells you whether your after-tax income covers your living expenses.
How to use it
- Pick your profile — age, filing status (single, married filing jointly, or head of household), and whether you're 65 or older.
- Enter your income sources in the relevant boxes. Capital gains use sale proceeds and cost basis, so only the gain is taxed while your basis is returned tax-free.
- Choose standard or itemized deductions — the calculator shows both and uses whichever helps you more, separately for federal and California (their rules differ).
- Add your expenses to see a coverage analysis: whether your after-tax cash actually covers what you spend, and how much gross income each source needs to net a target amount.
What it calculates
- Federal income tax across the 2025 brackets, with long-term capital gains and qualified dividends “stacked” on top of ordinary income at the correct 0%/15%/20% rates.
- California income tax using the 2025 state brackets — note that California taxes all capital gains as ordinary income (no preferential rate) and adds the 1% Mental Health Services Tax above $1 million.
- Social Security taxation — up to 85% may be federally taxable depending on your other income, while California exempts Social Security entirely.
- Net Investment Income Tax (3.8% above the threshold) and the 10% federal + 2.5% California early-withdrawal penalty on retirement accounts before age 59½.
- Effective and marginal rates, plus a gross-up showing the pre-tax income needed to hit a take-home goal.
California vs. federal: the big differences
California is one of the highest-tax states, and several of its rules diverge sharply from federal law. There is no preferential capital-gains rate — a long-term gain that's taxed at 15% federally can be taxed at 9.3% or more by California as ordinary income. California exempts Social Security benefits but has no SALT cap for its own return (while the federal deduction for state and local taxes is capped at $10,000). These differences are exactly why looking at federal tax alone understates the true cost of living on investment or retirement income in California.
Planning beyond a single year
A one-year snapshot is a great start, but big decisions — when to retire, when to do Roth conversions, when to sell appreciated stock or a rental — play out over decades. Our Retirement & Life Planner uses this same tax engine to project your taxes and net worth year by year across a timeline of life events, so you can compare scenarios side by side.
Frequently asked questions
- Is this an exact tax filing?
- No — it's an educational estimate using 2025 brackets and common rules. It doesn't replace tax software or a CPA, and it omits some credits and edge cases.
- Is my data sent anywhere?
- No. The calculator runs entirely in your browser; nothing you type is uploaded.
- Why is my California tax higher than I expected on capital gains?
- California taxes capital gains as ordinary income — there's no 0/15/20% break like the federal return — so investment income is taxed at your full state rate.
- Does it handle married filing jointly and head of household?
- Yes — choose your filing status in the profile section and all brackets, deductions, and thresholds update accordingly.