Bonus Withholding Explained: Why Your 22% Bonus Check Looks Taxed at 40%
Last updated · Bonuses
You earned a $10,000 bonus. You expected to take home about $7,800 after the 22% federal supplemental rate. Instead, your check shows about $6,200. Where did the extra $1,600 go? The "22 percent bonus tax" you read about is just one slice of a multi-tax stack, and your bonus is also subject to Social Security, Medicare, state, and local taxes — pushing the effective withholding rate to 35–45 percent for most earners. This guide explains the real math, why bonuses look over-taxed even when they aren't, and how to get the difference back at tax time.
The "22 percent rule" is just federal income tax
The IRS has two methods for withholding federal income tax on supplemental wages (bonuses, commissions, severance):
- Flat method: 22% federal income tax on the first $1 million of supplemental wages in a calendar year, then 37% on the portion above $1 million. Most employers use the flat method because it's simpler.
- Aggregate method: the bonus is added to your regular paycheck and withheld using your normal W-4 tax tables. Some employers use this for bonuses paid alongside a regular paycheck.
The 22% you read about is the flat method's federal income tax piece. It is NOT the total tax — you also pay Social Security, Medicare, state, and (sometimes) local tax on the same bonus.
The full tax stack on a $10,000 bonus
Here's what actually comes out of a $10,000 bonus paid to a typical California employee earning $120,000 base, single filer:
- Federal supplemental withholding (22%): $2,200
- Social Security (6.2%): $620 (assuming under wage base)
- Medicare (1.45%): $145
- California state withholding (10.23% supplemental rate): $1,023
- California SDI (1.1%): $110
- Total deductions: $4,098 (40.98%)
- Net check: $5,902
This is why the bonus "feels" like it was taxed at 41 percent. The 22% federal rate is just the largest single piece. State, FICA, and SDI add another 19 percent. The combined withholding rate is closer to 40-45 percent for most middle-to-upper earners.
Why supplemental withholding can over- or under-withhold
The 22% federal supplemental rate is a flat number, regardless of your actual marginal tax rate. This creates two cases:
- You're in the 22% federal bracket. The supplemental withholding exactly matches your marginal rate. No refund or owed amount at tax time from the bonus itself.
- You're in the 24% or higher federal bracket. The supplemental rate (22%) UNDER-withholds. You'll owe additional federal tax at tax time.
- You're in the 12% or lower federal bracket. The supplemental rate OVER-withholds. You'll get a refund of the difference at tax time.
For high earners in the 32-37% federal bracket, the supplemental withholding can under-withhold by 10-15 percentage points. A $50,000 bonus to a 32% bracket earner withholds 22% federally ($11,000) but actually owes 32% ($16,000) — a $5,000 shortfall that shows up at tax time as an unexpected balance due.
What about state supplemental rates
States that have income tax also have supplemental withholding rules. Common state supplemental rates:
- California: 10.23% on bonus and stock options, 6.6% on other supplemental wages. These are flat regardless of income.
- New York: 11.7% supplemental flat rate
- New Jersey: 5% to 9.9% (sliding scale)
- Massachusetts: 5% (matches the flat rate)
- Pennsylvania: 3.07% (matches the flat rate)
- Illinois: 4.95% (matches the flat rate)
Like the federal rate, these flat rates may over- or under-withhold compared to your actual liability. The difference is reconciled at tax time.
How to get over-withheld bonus tax back
If your supplemental withholding exceeded your actual tax liability, the difference is automatically refunded when you file your annual tax return. There's no separate process — the IRS calculates your total liability based on your full year's income, compares to total withholding (including the bonus), and refunds the difference.
If the over-withholding is significant and you don't want to wait until tax time, you can:
- Update your W-4 for the rest of the year to reduce regular paycheck withholding. This effectively "spreads" the over-withholding refund across remaining paychecks.
- Increase pre-tax contributions (401(k), HSA) to reduce taxable income going forward.
- Wait until tax time for the refund. Most people choose this for simplicity.
If your supplemental withholding was UNDER your actual liability (high earners), you may want to:
- Make estimated tax payments for the year to avoid an underpayment penalty
- Increase regular W-4 withholding by entering an additional dollar amount on Step 4(c)
- Set aside cash to pay the balance owed at tax time
When the aggregate method is better
Some employers use the "aggregate method" instead of the 22% flat rate. The aggregate method adds your bonus to your regular paycheck and applies your normal W-4 tax tables to the combined amount. The downside: it usually results in higher withholding because the tax tables assume the larger amount is your normal income for every paycheck.
Example: $5,000 regular biweekly pay + $20,000 bonus = $25,000 "paycheck." The W-4 tables apply, treating the $25,000 as if it's your regular biweekly amount, which puts you in the highest tax bracket. The result: aggregate method may withhold 35-45% federal, much higher than the 22% flat rate.
For most employees, the flat 22% rate is more favorable than the aggregate method — it under-withholds for high earners but produces a smaller "tax shock" on the bonus check itself.
Frequently Asked Questions
Why is my bonus taxed at 40 percent?+
It's not — the 22% you see is just the federal supplemental income tax rate. Add Social Security (6.2%), Medicare (1.45%), state withholding (varies), and state disability (in some states), and total withholding reaches 35-45% for most workers. The actual tax owed may be lower; the difference is refunded at tax time.
Can I get back the extra tax taken from my bonus?+
Yes, if your withholding exceeded your actual tax liability for the year. The difference is automatically refunded when you file your annual tax return. No separate action needed — the IRS reconciles all your withholding against your full-year income.
What is supplemental wage withholding?+
A simplified IRS withholding method for bonuses, commissions, and other supplemental wages. Flat 22% federal rate up to $1 million; 37% above $1 million. Many state taxes also use flat supplemental rates instead of normal W-4 tables.
Is bonus tax really 40%?+
No. The 22% federal rate is fixed; the rest depends on Social Security (6.2% if under wage base), Medicare (1.45% + 0.9% high-earner surcharge), state tax, and state disability. The combined withholding rate is typically 30-45% but the actual tax owed may be lower.
Why does my $10,000 bonus only give me about $6,000?+
Because of the multi-tax stack. Federal 22% + Social Security 6.2% + Medicare 1.45% + state tax (variable) + state disability (some states) = 35-45% total withholding. Net check is typically $5,500-$6,500 on a $10,000 bonus.
Should my employer use the flat method or aggregate method?+
Flat method is usually better for the employee because it caps federal income tax withholding at 22%. The aggregate method can withhold at much higher rates by treating the bonus as if it's your regular paycheck amount. Most employers use the flat method.
Will I owe extra tax on my bonus at tax time?+
Possibly, if you're in a federal tax bracket above 22% (i.e., earning above about $103K single in 2026). The flat 22% supplemental withholding under-withholds for high earners. Plan for an additional balance due, or make an estimated tax payment to avoid an underpayment penalty.