How Bonuses Are Taxed: Why Your Bonus Check Feels Smaller Than Expected

The "bonus tax" myth that will not die

Every year around bonus season, the same complaint surfaces: "The government taxes bonuses at a higher rate." This is wrong, but understandable. When you see 30%+ of your bonus disappear before it reaches your bank account, the conclusion feels obvious. But the explanation is about withholding mechanics, not tax rates.

The key distinction: tax rate (what you ultimately owe) is different from withholding rate (what your employer takes out of the check before giving you the money). Your bonus is withheld at a flat 22%, but it's taxed at your marginal rate, which for many workers is 12% or 22%. If those numbers don't match, the difference comes back to you at filing time.

Let's walk through exactly how this works, what you can do about it, and when to worry.

The two methods employers use to withhold bonus tax

The IRS, per Publication 15 (Employer's Tax Guide), allows two methods for withholding federal income tax on supplemental wages. Your employer picks one. You don't get a choice, but understanding which method they use explains why your check looks the way it does.

Method 1: The percentage (flat rate) method

This is the most common approach. Your employer withholds a flat 22% in federal income tax on monthly bonuses up to $1 million. It's clean and simple for payroll departments because they don't need to consider your W-4, filing status, or regular pay. They just multiply the bonus by 0.22 and send that to the IRS.

For bonuses exceeding $1 million, the excess above $1 million is withheld at 37%, the top federal bracket.

Method 2: The aggregate method

Some employers combine your bonus with your regular paycheck and calculate withholding on the total as if it were a single regular paycheck. This method can withhold either more or less than 22%, depending on how the combined total interacts with your W-4 settings and the tax brackets.

The aggregate method often withholds more than the flat rate because the combined amount pushes your payroll calculation into a higher annualized bracket. For example, if your normal biweekly pay is $2,500 and the bonus adds $5,000, the system calculates as though you earn $195,000 per year ($7,500 × 26 pay periods) and withholds accordingly, even though that annualized figure has nothing to do with your actual salary.

This over-withholding gets corrected at filing, but it can make your bonus check look even smaller than the flat 22% method would produce.

What about FICA? That part does not come back

Regardless of which method your employer uses for income tax, Social Security (6.2%) and Medicare (1.45%) are always withheld on bonus income. Combined, that is 7.65% on top of the income tax withholding. Unlike income tax over-withholding, FICA taxes are generally not refundable through your annual return unless your combined wages from all employers exceed the Social Security wage base (which is updated annually by the SSA).

So on that $5,000 bonus, $382.50 goes to FICA regardless. This is a real cost, not a timing difference.

Four strategies to keep more of your bonus

1. Max out your 401(k) in the bonus pay period

If your employer allows it, increase your 401(k) contribution to the maximum for the pay period your bonus is paid. A $5,000 bonus directed entirely into a traditional 401(k) reduces federal taxable income by $5,000, meaning zero income tax withheld on that amount. You still pay FICA, but the income tax savings are immediate. Use our take-home optimizer to see how retirement contributions affect your net pay.

2. Ask about your employer's withholding method

If your employer uses the aggregate method and your effective tax rate is well below 22%, ask the payroll department if they can apply the flat rate method instead. Not all employers will switch, but some will if asked.

3. Adjust your W-4 after the bonus

If you know the bonus will be over-withheld, you can temporarily increase your W-4 allowances to reduce withholding on regular paychecks for the remainder of the year, effectively recovering the overpayment before filing season. Use the IRS Tax Withholding Estimator to get the adjustment right. Be careful not to under-withhold too much, or you may owe at filing.

4. Use HSA or FSA contributions

Health Savings Account and Flexible Spending Account contributions are pre-tax. If you have not maxed out your HSA for the year, directing bonus funds there reduces taxable income while building a healthcare fund you control.

When high earners need to worry about bonus tax

For workers with total income (salary + bonus + other sources) exceeding $200,000 as a single filer, additional considerations apply:

• Additional Medicare tax: 0.9% on income above $200,000 (single) or $250,000 (married filing jointly)
• Net investment income tax: 3.8% on investment income if modified AGI exceeds $200,000 (single)
• Higher marginal brackets: A large bonus on top of a high salary may push total income into the 32% or 35% bracket, where the 22% flat withholding actually under-withholds

In these cases, you may owe additional tax at filing rather than receiving a refund. Check your total tax picture with our tax breakdown tool to avoid surprises.