California Bonus Tax Calculator (2026)
See exactly what the IRS and California EDD take from your bonus, and what actually lands in your account.
Your bonus details
Estimate only, not tax advice. Based on 2026 IRS and California EDD flat supplemental withholding rules.
California sets its own flat bonus withholding, 10.23% for cash bonuses and stock pay, or 6.6% for other supplemental wages. Add the federal 22%, 7.65% FICA, and 1.3% SDI, and a typical CA bonus loses 30% to 35% upfront.
That is withholding, not your final bill. If your real tax rate is lower, the difference comes back as a refund.
| Federal supplemental (flat method) | 22% up to $1M, 37% above |
| California supplemental, cash bonus / stock | 10.23% |
| California supplemental, other pay | 6.6% |
| Social Security | 6.2% up to $184,500 wage base |
| Medicare | 1.45% (2.35% above $200,000 YTD wages) |
| California SDI | 1.3%, no wage cap |
Rough take-home by bonus size, under the Social Security cap:
| $1,000 cash bonus | ~$588 net |
| $5,000 cash bonus | ~$2,941 net |
| $10,000 cash bonus | ~$5,882 net |
| Over $1,000,000 cumulative | federal jumps to 37% on the excess |
Employers pick the method, not you. Flat (used above) taxes the bonus on its own. Aggregate folds it into your next paycheck and taxes the combined total, often withholding more upfront. Same final tax either way, just a different withholding pattern.
This tool shows exactly how much of your bonus disappears to federal tax, California tax, Social Security, Medicare, and SDI before it hits your account. Built for California employees getting a cash bonus, commission, or stock-related payout, part of our full California payroll tax library. Skip the guesswork on payday and see your real number in seconds.
Uses the IRS 2026 flat supplemental rate (22%/37%) and the California EDD supplemental withholding rate (10.23% or 6.6%).
How to Use the California Bonus Tax Calculator
Step 1: Enter your gross bonus amount.
Step 2: Pick your payment type, cash bonus or stock at 10.23% (see our full California bonus tax rate breakdown), or other supplemental pay like severance at 6.6%.
Step 3: Enter your year-to-date wages before this bonus, so the tool can check the Social Security cap and the Additional Medicare threshold.
Step 4: Enter your 401(k) contribution deferral percentage, if any, from this bonus.
Step 5: Flag it if your cumulative supplemental wages this year already passed $1,000,000.
The result updates live as you type, no submit button needed.
Pro Tips
- Entering $0 for year-to-date wages overstates your Social Security withholding if you’ve actually earned wages earlier in the year.
- A 401(k) deferral lowers income tax withholding but not Social Security, Medicare, or SDI, those still apply to the full bonus.
- The 22% federal rate is withholding, not your final tax bill. Your actual liability depends on your real California tax bracket, set when you file.
How California Bonus Tax Is Calculated
Formula: Net Bonus = Gross Bonus − Federal Withholding − CA Withholding − Social Security − Medicare − SDI − 401(k) Deferral
| Item | Rate | On $10,000 Bonus |
|---|---|---|
| Federal withholding | 22% | $2,200 |
| California withholding | 10.23% | $1,023 |
| Social Security | 6.2% | $620 |
| Medicare | 1.45% | $145 |
| California SDI | 1.3% | $130 |
| Net take-home | (total) | $5,882 |
Example assumes $0 prior year-to-date wages and no 401(k) deferral.
California Bonus Tax Rates for 2026
- Federal supplemental withholding: 22% up to $1,000,000, 37% above.
- California supplemental rate, cash bonus/stock: 10.23%.
- California supplemental rate, other pay (severance, commission): 6.6%.
- Social Security: 6.2%, wage base $184,500 for 2026 (up from $176,100 in 2025).
- Medicare: 1.45%, plus 0.9% Additional Medicare on wages over $200,000.
- California SDI: 1.3% for 2026 (up from 1.2% in 2025), no wage cap. Full breakdown in our California SDI calculator.
California Bonus Tax Calculator, Full Feature List
Inputs:
- Bonus amount ($)
- Payment type (cash bonus/stock at 10.23%, or other supplemental pay at 6.6%)
- Year-to-date wages before this bonus ($)
- 401(k) deferral from this bonus (%)
- Cumulative supplemental wages over $1,000,000 this year (yes/no)
Modes/Options:
- Live auto-calculate on every input change, no button needed
Outputs:
- Net take-home dollar amount, alongside a full gross pay vs net pay style breakdown
- Net take-home as a percentage of gross bonus
- Visual net-vs-tax bar
- Full withholding breakdown table (federal, CA, Social Security, Medicare, Additional Medicare when triggered, SDI, 401(k) deferral)
- Contextual flags: Social Security cap reached, Additional Medicare triggered, $1M supplemental threshold crossed
What’s Included in This Calculator
- 2026 federal and California supplemental withholding rates
- Social Security wage base cap logic for 2026
- Additional Medicare Tax logic above $200,000
- California SDI on the full bonus amount, no cap
Why This Calculator Is Different
Most bonus calculators run every state through the same federal formula and call it done. This one is built around California’s own rules, so nothing gets flattened into a national average.
- Real California rates, not a guess. Uses the EDD’s actual 10.23% (cash bonus/stock) and 6.6% (other supplemental pay) rates instead of one generic state number.
- Checks your Social Security cap for you. Applies the $184,500 2026 wage base automatically, so you’re never overcharged past it.
- Catches the Additional Medicare Tax. Flags and adds the extra 0.9% above $200,000, a step most calculators skip.
- Prices in California SDI. SDI has no wage cap in California, and it’s easy to forget on a bonus. It’s built into every result here.
- Handles a 401(k) deferral from the bonus itself. Lowers your income tax withholding correctly, while still taxing the full amount for Social Security, Medicare, and SDI, the way payroll actually works.
- No button, no reload. Change any input and the result updates immediately, so you can test a few scenarios in seconds.
Use it if you want a real number, not a rough estimate. A generic bonus calculator can tell you what a 22% federal rate looks like. This one tells you what actually lands in your California bank account.
What Is Bonus Withholding in California?
A bonus is “supplemental wages” under IRS and California rules, taxed differently than your regular paycheck. Employers can withhold at a flat rate instead of using your W-4 or DE 4 tables. Federal withholding is 22% (37% above $1 million in cumulative supplemental wages per year). California withholds separately at 10.23% for cash bonuses and stock pay, or 6.6% for other supplemental wages. This applies to anyone paid a bonus, commission, severance, or stock-related payout while working in California. It matters most at bonus time and stock vesting, when the withheld amount can look much smaller than expected.
Flat Rate vs. Aggregate Method
| Flat Rate Method | Aggregate Method | |
|---|---|---|
| How it’s taxed | Bonus taxed on its own at fixed rates | Bonus combined with your next paycheck, taxed as one amount |
| Who chooses it | Employer | Employer |
| Typical impact | Simpler, predictable | Can withhold more upfront for higher earners, see our Method B exact calculation guide |
| Final tax owed | Same either way | Same either way |
Frequently Asked Questions
Is a bonus taxed higher than regular income in California?
No, not in final tax owed. It’s withheld at a flat rate upfront, which often looks higher than your regular paycheck withholding.
What is the California bonus tax rate for 2026?
10.23% for cash bonuses and stock-related pay, 6.6% for other supplemental wages, on top of federal and FICA taxes.
Will I get some of my bonus withholding back?
Yes, if your actual tax bracket is lower than the flat withholding rate, the difference comes back as part of your refund. You can check your California refund status once you file.
Does 401(k) deferral reduce all taxes on my bonus?
No. It lowers income tax withholding only. Social Security, Medicare, and SDI still apply to the full bonus amount.
What happens to Social Security tax on a large bonus?
Once your year-to-date wages plus bonus pass $184,500 (2026 wage base), the amount above that is not taxed for Social Security.
Why did my employer withhold more than 22% federal on my bonus?
Some employers use the aggregate method, combining your bonus with regular pay, which can push withholding higher based on your W-4.
Related Tools
- California Paycheck Calculator, our main paycheck calculator. Estimate your regular take-home pay per paycheck.
- Annual Salary Calculator, convert an hourly rate or salary into your full annual take-home.
- California Bonus Tax Rate Guide, a full breakdown of the 10.23%/6.6% rates used in this calculator.
- California SDI Calculator, estimate State Disability Insurance withholding on regular wages.
- 401(k) Contribution Limits, see the 2026 limits before setting your deferral percentage.
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