California taxes bonuses as regular income, not at a special rate

A bonus is treated the same way as your regular paycheck for California state income tax purposes. Your employer withholds state tax from the bonus at the same rate they withhold from your ordinary wages, based on your tax bracket and filing status. There is no separate "bonus tax" in California — the state does not tax bonuses differently than salary or hourly pay.

However, federal income tax withholding on bonuses sometimes works differently than state withholding. Your employer may use the "aggregate method" (adding the bonus to your regular paycheck and calculating tax on the total) or the "percentage method" (withholding a flat 22% or 37% depending on bonus size). This can mean your federal withholding is higher or lower than your state withholding, even though both treat the bonus as ordinary income.

Key Takeaways

  • California withholds state income tax on bonuses at your regular tax bracket rate, the same as your salary.
  • Federal withholding on bonuses may use a flat percentage (22% or 37%) instead of your normal bracket, which can result in over-withholding or under-withholding.
  • Self-employed people and contractors must set aside money for both state and federal self-employment tax on bonus income.
  • If your bonus pushes you into a higher tax bracket, you may owe additional state tax when you file your return.
  • Bonuses are subject to Social Security and Medicare taxes (FICA) just like regular wages, up to the annual Social Security wage cap.

How California calculates withholding on your bonus

Your employer uses your W-4 form to determine how much California state tax to withhold. The state applies your tax bracket directly to the bonus amount. California has nine tax brackets ranging from 1% to 13.3%, depending on your total income for the year. If your bonus is large enough to push you into a higher bracket, your employer may withhold at that higher rate on the bonus itself.

The withholding is not a final calculation — it is an estimate. If you receive a large bonus late in the year, your employer may not withhold enough to cover your full state tax liability, especially if the bonus moves you into a higher bracket. You may owe additional tax when you file your California return in April. Conversely, if you over-withhold, you will receive a refund.

Federal withholding on bonuses works differently

The IRS allows employers to use two methods for federal withholding on bonuses. The aggregate method combines your bonus with your regular paycheck and calculates federal tax as if that combined amount were your normal pay. The percentage method withholds a flat rate: 22% on bonuses up to $1 million, and 37% on bonuses over $1 million (for 2024).

Most employers use the percentage method because it is simpler. This often results in higher federal withholding than you would owe based on your actual tax bracket, especially if you are in the 12% or 22% federal bracket. You may see a refund of the over-withheld amount when you file your federal return, or you can adjust your W-4 to reduce withholding on future paychecks if you expect more bonuses.

FICA taxes (Social Security and Medicare) on bonuses

Bonuses are subject to FICA taxes just like regular wages. Your employer withholds 6.2% for Social Security and 1.45% for Medicare, and the employer pays a matching amount. These withholdings explore to all bonus income, with one exception: the Social Security portion (6.2%) only applies to wages up to the annual cap, which is $168,600 for 2024. Once you reach that cap in a calendar year, no more Social Security tax is withheld on bonuses or any other wages for the rest of that year.

Medicare tax has no wage cap. You pay 1.45% on all bonus income, and if your total wages exceed $200,000 (single) or $250,000 (married filing jointly), an additional 0.9% Medicare tax applies to the excess. This additional tax is withheld by your employer if your bonus pushes you over the threshold.

What happens if you are self-employed or a contractor

If you receive a bonus as a self-employed person or independent contractor (reported on a 1099 form), you are responsible for paying both the employee and employer portions of Social Security and Medicare tax. This is called self-employment tax, and it totals 15.3% (12.4% Social Security plus 2.9% Medicare). You do not pay this through withholding — instead, you set aside the money and pay it when you file your tax return, or make quarterly estimated tax payments.

You must also pay California state income tax on the bonus. Unlike W-2 employees, no tax is withheld automatically, so you need to estimate what you owe and either pay it quarterly or set aside a lump sum to pay when you file. Many self-employed people underpay because they do not set aside enough from bonus income. A safe approach is to reserve 30% to 40% of any bonus for taxes.

Bonuses that push you into a higher tax bracket

California uses progressive tax brackets, meaning your tax rate increases as your income rises. If your bonus is large, it may push your total income into a higher bracket. Your employer should withhold at the higher rate on the bonus itself, but this is not may provide — it depends on how your W-4 is filled out and how your employer processes the bonus.

If your employer under-withholds, you will owe the difference when you file your return. For example, if you earn $80,000 in salary (taxed at 9.3%) and receive a $50,000 bonus that pushes your total to $130,000 (taxed at 10.3%), you owe an extra 1% on the $50,000 bonus. If your employer only withheld at 9.3%, you will owe about $500 more at tax time. You can reduce this risk by adjusting your W-4 after receiving a large bonus, or by making a voluntary tax payment to your state account.

Timing of bonuses and tax withholding

The timing of when you receive a bonus affects how much tax is withheld. A bonus received in December is part of your 2024 income and is taxed based on your 2024 bracket. A bonus received in January is part of your 2025 income. If you receive a large bonus near the end of the year, your employer may not have time to adjust withholding on your final paychecks, which can leave you short on taxes owed.

Some employers offer bonuses in the form of a separate check rather than adding it to your regular paycheck. This does not change the tax treatment — it is still ordinary income — but it may affect how withholding is calculated. A separate bonus check may be subject to the flat percentage method for federal withholding, which often results in higher federal tax being withheld than if the bonus were combined with your regular pay.

Frequently Asked Questions

Do I have to pay taxes on a bonus in California?

Yes. Bonuses are taxed as ordinary income by both California and the federal government. Your employer withholds state and federal income tax, plus Social Security and Medicare tax, from the bonus. The amount withheld depends on your tax bracket and filing status.

Why is my federal withholding on my bonus so high?

The IRS allows employers to withhold a flat 22% (or 37% on very large bonuses) for federal income tax on bonuses, rather than using your normal tax bracket. This often results in over-withholding if you are in a lower bracket. You will receive the excess back as a refund when you file your federal return.

What if my bonus is paid after I reach the Social Security wage cap?

Once your total wages reach $168,600 in a calendar year (for 2024), no more Social Security tax (6.2%) is withheld on any bonus or paycheck for the rest of that year. Medicare tax (1.45%) continues to be withheld on all bonus income regardless of the cap.

Can I adjust my withholding after receiving a large bonus?

Yes. You can submit a new W-4 form to your employer to increase or decrease your withholding on future paychecks. If you expect to owe taxes on the bonus, you can also make a voluntary payment directly to the California Franchise Tax Board or the IRS before the filing important date.

Are bonuses taxed differently if I am self-employed?

Self-employed bonuses are not subject to withholding, so you must set aside money yourself for both state income tax and self-employment tax (15.3% total for Social Security and Medicare). Many self-employed people reserve 30% to 40% of bonus income for taxes to avoid owing a large amount at filing time.