DayCents

Taxes

Bonus and RSU Tax Calculator

Bonuses and vesting shares are withheld at a flat supplemental rate — 22% federally, regardless of your bracket. If you are in the 32% bracket, that gap is not forgiven. It becomes a bill you meet at filing, often without warning.

Tested against worked examplesHow we verify

0 in states without an income tax. California uses 10.23% for bonuses.

You receive: $13,070

You receive

$13,070

After 34.6% withheld at source.

Set aside $2,000 now. The flat 22% withholding is below your marginal rate, and the difference is due at filing — this is the single most common April surprise for people with equity compensation.

Federal withheld
$4,400
State withheld
$1,000
Social Security and Medicare
$1,530
Total withheld
$6,930
Tax actually owed
$8,930
Additional tax due at filing
$2,000
The gross amount$20K
You keep$11,07055%
Withheld at source$6,93035%
Owed in April$2,00010%

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Compare scenariosTry three values of one input
Bonus and RSU Tax Calculator results for three values of Bonus or vesting value
Bonus or vesting value
You receive$11,763$13,070+$1,307$14,377+$2,614
Federal withheld$3,960$4,400+$440$4,840+$880
State withheld$900$1,000+$100$1,100+$200
Social Security and Medicare$1,377$1,530+$153$1,683+$306
Total withheld$6,237$6,930+$693$7,623+$1,386
Tax actually owed$8,037$8,930+$893$9,823+$1,786

Every other input stays at the value you set above — currently $20,000 for bonus or vesting value. Differences are measured against the first column.

Saved scenariosSave this calculation

Saved in this browser only — no account, and nothing is sent to us. Clearing your browser data deletes them.

How this calculator works

Withholding is the flat supplemental rate you select, applied to the gross amount, plus the state supplemental rate and FICA. FICA is 7.65% below the Social Security wage cap and 1.45% above it, since only Medicare continues. Actual tax owed is your combined federal and state marginal rates on the amount plus the same FICA. The difference is what settles at filing.

A single marginal rate stands in for progressive brackets, so a bonus that spans brackets is approximated. The 0.9% Additional Medicare Tax above $200,000, state disability withholding, and the timing of RSU sales — where price movement between vesting and sale creates a separate capital gain or loss — are not modelled.

What this assumes

  • Supplemental wages are typically withheld at a flat federal rate rather than at your marginal rate — this is withholding, not your final tax.
  • The difference is settled on your return: over-withholding comes back as a refund, under-withholding as a bill.
  • FICA applies to a bonus exactly as to salary, up to the Social Security wage base.

What changes this number

Withholding versus actual tax
The main confusion this calculator exists to clear. A bonus is not taxed at a higher rate; it is withheld at a different one.
Your total income for the year
Determines the real rate the bonus is eventually taxed at, once the return is filed.
Deferring into a 401(k)
Many plans allow a bonus to be contributed, which moves it out of this year's taxable income entirely.

A worked example

Take the $20k bonus in the 32% bracket scenario. These figures are produced by the calculator above, not written alongside it, so they always match what the tool returns.

What you enter

Bonus or vesting value
$20,000
State supplemental rate
5%
Your federal marginal rate
32%

What it returns

You receive
$13,070
Federal withheld
$4,400
State withheld
$1,000
Social Security and Medicare
$1,530
Total withheld
$6,930

Set aside $2,000 now. The flat 22% withholding is below your marginal rate, and the difference is due at filing — this is the single most common April surprise for people with equity compensation.

Try an example

Frequently asked questions

How are bonuses taxed?

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.

Why do RSUs leave me owing tax in April?

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.

Can I have more withheld from a bonus?

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.

Is the 22% rate always used?

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.

Does a bonus push me into a higher bracket?

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.

Disclaimer: DayCents provides this calculator for educational purposes only. Results are estimates based on your inputs and the stated assumptions — they are not financial advice, a quote, or an offer of credit. Consult a qualified financial professional before making major money decisions.