Bonus and RSU Tax Calculator

Not at a special rate — they are ordinary income, taxed like salary. What differs is withholding. Employers may use a flat supplemental rate of 22%, or add the bonus to a regular paycheck and withhold at the aggregate rate. Either way the final tax is settled on your return.

Vesting shares are withheld at the same flat 22%, usually by selling some of the shares. Anyone in the 32% or 35% bracket is short by 10–13 points of the vesting value. On $100,000 of vesting that is $10,000–$13,000 due at filing, and nothing warns you.

Not from the supplemental rate itself — it is fixed by regulation. What you can do is increase withholding on regular pay via Form W-4 line 4(c), or make a quarterly estimated payment. Withholding is treated as paid evenly across the year, which makes it the cleaner fix.

Only for supplemental wages up to $1 million in a calendar year. Above that, the excess is withheld at 37%, the top rate, and the employer has no discretion. Employers may also use the aggregate method instead, which withholds as though the bonus were regular pay.

Only the portion above the threshold is taxed at the higher rate — brackets are marginal, not cliffs. A bonus that crosses a bracket line does not re-tax your salary. What it can do is affect phase-outs of credits and deductions, which behave more like cliffs.