What ADP actually calculates
ADP's bonus tool defaults to the IRS flat supplemental rate: 22% federal on the bonus up to $1M, 37% above it, plus full FICA and state supplemental rates. The aggregate method (bonus added to a regular check) is the alternative employers may use instead.
Why this never matches your stub to the dollar
Any paycheck estimator — theirs or ours — is missing things only your employer knows.
- • Your filed W-4: dependents, other income, and extra withholding all shift the number.
- • Post-tax deductions: union dues, garnishments, ESPP, life insurance, parking.
- • Local taxes: city wage taxes (NYC, Philadelphia, Detroit, Columbus) and school-district levies.
- • State disability and paid-leave premiums: CA SDI, NY PFL, WA Cares, NJ TDI.
- • Mid-year raises, bonuses, and hitting the Social Security cap change later checks.
How our version differs from the brand's tool
ADP's public tool is a lead-in to their payroll product and asks for your W-4 line by line. Ours trades that granularity for speed: six inputs, an instant answer, a full line-by-line breakdown, and shareable results. Use ours to sanity-check an offer or plan a change; use your employer's payroll portal for the number that will actually hit your account.
Flat rate vs aggregate method
Employers may withhold on a bonus two ways. The percentage (flat) method taxes it at a straight 22% federal — simple, and what most large payroll systems do. The aggregate method adds the bonus to a regular paycheck and withholds as if you earn that much every period, which can withhold 30–40% on a big bonus. Either way, the actual tax owed is settled at filing; the difference only changes your refund.
FAQ
Is this the official ADP calculator?
No. RevenueLab is independent and not affiliated with ADP. This page runs the same publicly described method with 2026 figures so you can get the number without a sign-up or a sales follow-up.
How accurate is a ADP-style bonus estimate?
Within a few percent for a standard W-4 with no local taxes. It will drift on anything your employer knows and we don't: local wage taxes, state disability premiums, post-tax deductions, and mid-year pay changes.
Why was my bonus taxed at 40%?
It probably was not taxed at 40% — it was withheld at 22% federal plus 7.65% FICA plus state, and possibly through the aggregate method which annualises the check. Withholding is not the tax you owe; the difference comes back as refund.
Does this handle 2026 tax rates?
Yes — 2026 federal brackets, the $15,750 single standard deduction, and the $184,500 Social Security wage base are all built in.
How this calculator is built
Independently maintained
Written by Sam Doshi and the RevenueLab editorial team. We don't sell the data feeds this tool is built on.
Sourced from primary data
Benchmarks come from public AdSense / Stripe / IRS disclosures and reader-submitted data — never third-party "$X per view" claims. Full methodology.
Last editorial review
Reviewed on a rolling quarterly cycle. Dated reviews are published on the methodology record for each calculator.
Editorial standards
See our editorial policy and disclaimer. Results are estimates, not advice.