ADP Bonus Tax Rate: Flat 22%, Aggregate, and $1M Rule

The ADP bonus tax rate for federal income tax is either a flat 22% or an aggregate rate calculated from your regular wages and W-4 — your employer picks which one, and the choice can produce very different numbers on your stub. On top of that federal piece, Social Security and Medicare take another 7.65%, and most states withhold something too. Total withholding on a typical bonus usually falls between 30% and 40% of the gross.

The Two Federal Methods ADP Can Use

The IRS lets employers calculate withholding on bonuses and other supplemental wages (commissions, severance, back pay, overtime) using one of two methods.¹ Your employer chooses. You don’t.

Flat 22% Method

The simple option. The employer withholds exactly 22% of the bonus for federal income tax, regardless of what’s on your W-4. A $5,000 bonus produces $1,100 in federal withholding, no matter your filing status or dependents. This method is only available when the bonus is identified separately from regular wages in payroll records. If it’s lumped into a regular paycheck with no distinction, the employer must treat the whole payment as ordinary wages.¹

Aggregate Method

The aggregate method combines your bonus with your regular wages for the same pay period and calculates withholding on the combined total as a single paycheck, using the standard IRS tables and your W-4 elections. Tax already withheld (or scheduled to be withheld) from your regular wages is subtracted, and the remainder comes out of the bonus.¹

The catch is annualization. The withholding tables ask, in effect, “if this person earned this much every pay period, what bracket would that put them in?” A $10,000 bonus stacked on a $4,000 biweekly paycheck looks to the system like $14,000 every two weeks, or $364,000 a year. That pushes the calculation into the 32% or 35% bracket even though your real annual income is much lower. Result: withholding on the bonus portion that runs well above 22%.

The flip side: if your regular pay plus bonus still falls in the 10% or 12% bracket on an annualized basis, aggregate withholding can come out below 22%.

Why Your Bonus Stub May Not Show 22%

ADP’s payroll platforms support both methods, and in many configurations the default is aggregate. The system pulls in your W-4 and applies standard withholding tables to any payment it processes. Using the flat 22% requires the payroll administrator to make an active selection in the supplemental earnings or special pay setup.²

If your bonus stub shows federal withholding noticeably above or below 22%, the aggregate method was almost certainly used. Ask your payroll department which method they picked. It can vary from one bonus run to the next, and it belongs to your employer, not to ADP or to you.

Social Security, Medicare, and State Tax Come Out Too

The 22% or aggregate rate is only the federal income tax slice. Bonuses face the same FICA taxes as any other wages.¹

Social Security: 6.2% on earnings up to $184,500 in 2026. Once your year-to-date wages pass that cap, no more Social Security tax comes out.³
Medicare: 1.45% on all earnings, no cap.⁴
Additional Medicare Tax: an extra 0.9% once your year-to-date wages cross $200,000, which your employer starts withholding automatically regardless of your filing status.⁵

Below the Social Security cap, FICA alone takes 7.65% of the bonus. Add the 22% flat federal rate and you’re at 29.65% before state tax enters the picture.

Most states with income tax also withhold on bonuses. Some set their own flat supplemental rate, roughly 3% to over 13%; others use their regular withholding tables. A handful of states have no income tax and therefore no state-level bonus withholding. ADP applies the correct state supplemental rate automatically based on your work location. Between federal, FICA, and state tax, total withholding on a bonus typically runs 30% to 40%, and higher for employees in high-tax states whose income has already cleared the Social Security wage cap.

The $1 Million Rule

Once your total supplemental wages from one employer exceed $1 million in a calendar year, the excess is withheld at a mandatory 37% — the top individual income tax rate. Your employer has no discretion on this piece.¹ The first $1 million can still use the flat or aggregate method. The threshold is cumulative across the year, and the payroll system tracks the running total. This rate was permanently set when Congress extended the individual rate structure through P.L. 119-21 in 2025.⁶

Withholding Is a Prepayment, Not the Final Bill

Whatever percentage came out of your bonus is a prepayment toward your annual tax bill. Your actual liability gets settled when you file Form 1040, based on your total income, deductions, and credits.⁷

The flat 22% only lines up cleanly if your annual taxable income lands in the 22% bracket. Earn less overall and you’ll get some of the withheld amount back as a refund. Earn more, and you’ll owe the shortfall at filing. The aggregate method has the opposite tendency: because it annualizes one large paycheck, it usually over-withholds on a bonus that’s large relative to your regular pay. Either way, the paycheck math and the tax return math don’t have to match.

What You Can Do About Bonus Withholding

You can’t pick the method. You can adjust the surrounding withholding.

Form W-4 line 4(c) lets you request an additional flat dollar amount of federal withholding per pay period, and your employer must honor a request for more withholding.⁸⁹ If you know a bonus is coming and your projected tax will exceed what’s currently being withheld, add to line 4(c) before the bonus pay period. Submit a new W-4 afterward to bring things back to normal, or you’ll keep overpaying on every subsequent check.

Running the other way: if a bonus over-withheld and you don’t want to wait until filing to recover the money, adjust your W-4 to reduce withholding on the rest of the year’s paychecks. Neither move changes the bonus itself. Both change the yearly total so you land closer to break-even at filing.

Gross-Up Bonuses

Some employers promise a bonus as a specific after-tax amount, say $5,000 net. Delivering that requires grossing up: calculating a larger gross so the employee ends up with the promised net after withholding. Using the flat method:

Gross bonus = Desired net ÷ (1 − combined tax rate)

The combined rate stacks federal (22%), Social Security (6.2%), and Medicare (1.45%) for 29.65%. To net $5,000:

$5,000 ÷ 0.7035 = $7,109.45

State income tax, if any, gets added to the combined rate before you run the calculation. ADP’s paycheck calculator handles the back-math automatically once the administrator enters the target net.² If you were promised a net amount and the numbers don’t match on your stub, ask whether the gross-up covered state and local taxes or only federal.

Year-End Timing

A bonus that hits around New Year’s counts as income in the year it becomes available to you, not the year your employer decides to pay it. A direct deposit landing December 31 is that year’s income. A check the employer holds until January 2 is next year’s income. If a bonus is credited to your account but your access is restricted until a future date, the restricted credit alone doesn’t count as income; taxability starts when the restriction lifts.¹⁰ Worth watching if you’re near a bracket boundary or timing deductions.

1
Internal Revenue Service. Publication 15 (2026), (Circular E), Employer’s Tax Guide – Section: 7. Supplemental Wages
2
ADP. EasyPayNet Bonus Payrolls
3
Social Security Administration. Contribution and Benefit Base
4
Social Security Administration. 2026 Cost-of-Living Adjustment (COLA) Fact Sheet
5
Internal Revenue Service. Topic No. 560, Additional Medicare Tax
6
GovInfo. Public Law 119-21
7
Internal Revenue Service. About Form 1040, U.S. Individual Income Tax Return
8
Internal Revenue Service. Form W-4, Employee’s Withholding Certificate
9
Internal Revenue Service. Withholding Compliance Questions and Answers
10
eCFR. 26 CFR 1.451-2 – Constructive Receipt of Income