Why is so much tax taken out of my bonus?

Bonuses use the IRS flat "supplemental wage" withholding rate of 22% rather than your normal paycheck rate, which can look high if your marginal rate is below 22%. It is only withholding — if too much is withheld, you get it back when you file your annual return.

Is my data sent anywhere when I use this calculator?

No. All calculations run entirely in your browser using JavaScript. No amounts, inputs, or personal data are ever transmitted to any server.

Wisconsin Bonus Tax Calculator 2025 — Supplemental Wage Withholding

Q: What is the bonus tax rate in Wisconsin?

Wisconsin does not use a single flat bonus (supplemental) rate. Employers combine the bonus with your regular wages and withhold using the standard Wisconsin wage tables (the aggregate method), so the exact state amount depends on your normal paycheck. Federally, the flat supplemental rate is 22% (37% above $1,000,000).

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Wisconsin Bonus Tax Calculator 2025

A bonus is a supplemental wage, and it is taxed differently from a normal paycheck. The federal government withholds a flat 22% on supplemental wages up to $1,000,000 in a year (37% on anything above that), plus FICA. Wisconsin does not publish a single flat supplemental rate. Employers add the bonus to a regular paycheck and withhold using the standard Wisconsin wage tables (the aggregate method), so the state portion depends on your normal pay.

Enter your bonus below. The calculator shows federal supplemental withholding, Social Security (6.2% up to the $176,100 wage base) and Medicare (1.45%, plus 0.9% above $200,000), the Wisconsin state portion, and your real take-home. Everything runs in your browser — no amounts or personal data are transmitted.

Important: Wisconsin’s supplemental withholding is tiered by annual wages (about 3.54%–7.65%); this uses the regular (aggregate) method. Verify the current figure with the Wisconsin Department of Revenue.