How Bonus Withholding Really Works (And Why You Might Get Some Back)
A $5,000 bonus that arrives as $3,600 in your bank account feels like a tax penalty, but it usually isn't — it's a withholding quirk. Bonuses are taxed as "supplemental wages" using rules that are deliberately conservative, which means many people are overwithheld on bonus checks and recover the difference at tax time. This guide explains the two withholding methods, what FICA still takes, and how to read your bonus stub correctly.
An Expert Perspective: Withholding Is Not the Same as Your Tax Bill
Tax professionals see confusion every bonus season because people treat the withheld amount as final. It rarely is.
- 22% Is a Withholding Rate, Not Your Tax Rate: If your actual marginal tax bracket is lower than 22%, the difference comes back to you as part of your refund. If it's higher, you may owe more when you file.
- The Aggregate Method Can Look Worse Short-Term: When a bonus is combined with a regular paycheck and taxed at that period's higher marginal rate, withholding can spike — but your annual tax liability does not change because of which method your employer chose.
What Gets Deducted From a Bonus
| Item | Type | Impact | Notes |
|---|---|---|---|
| Federal Supplemental Tax | Flat or Aggregate | High | Flat 22% standard rate; 37% above $1 million in supplemental wages |
| FICA | Flat Payroll Tax | Medium | 7.65% unless you've already hit the Social Security wage base for the year |
| State Tax | Varies by State | Low to Medium | Some states apply their own supplemental rate; others use the regular rate |
| True-Up at Filing | Reconciliation | Refund or Owe | Annual return settles the gap between withheld and actual liability |
Worked Example: A $12,000 Year-End Bonus
Take a $12,000 bonus taxed using the flat supplemental method. Federal withholding at 22% removes $2,640. FICA at 7.65% removes $918. A 4.5% state tax rate removes $540. Total withholding comes to $4,098, leaving a net bonus of $7,902 — about 65.9% of the gross amount. If this employee's actual marginal federal rate is only 12%, roughly $1,200 of that federal withholding will likely return as part of their refund the following spring.
Planning Around a Bonus
Because bonus withholding is often conservative, some employees choose to increase 401(k) contributions specifically during a bonus payout to reduce the taxable portion, while others adjust their W-4 afterward if they consistently see large refunds. Either approach works best when you know your actual marginal rate ahead of time rather than reacting after the smaller-than-expected deposit arrives.
Frequently Asked Questions (FAQ)
Q: Why is my bonus taxed at a flat 22% instead of my normal tax rate?
A: The IRS classifies bonuses as "supplemental wages," and most employers use the flat 22% federal rate for amounts under $1 million. This is just a withholding method — your actual liability is settled when you file, and you may get some back as a refund.
Q: What is the "aggregate method" of bonus withholding?
A: Your employer adds the bonus to your most recent paycheck and withholds on the combined total as one larger paycheck. This often withholds more than the flat 22% method, even though your annual tax liability stays the same.
Q: Do I still pay FICA tax on a bonus?
A: Yes. Bonuses are subject to the standard 7.65% FICA tax just like regular wages, unless you've already hit the annual Social Security wage base, in which case only the 1.45% Medicare portion continues.
Q: Will withholding more on my bonus mean I pay more total tax for the year?
A: No. Withholding is a prepayment, not the final bill. Excess withholding from a bonus is reconciled as a larger refund (or smaller balance due) when you file your tax return.
Q: Are bonuses over $1 million taxed differently?
A: Yes. The portion of supplemental wages exceeding $1 million in a calendar year is subject to a mandatory 37% federal withholding rate rather than the standard 22% flat rate.