RSU Tax Calculator

Estimate the tax on vesting RSUs and whether the standard 22% or 37% withholding will leave you owing more at tax time.

$
$

Salary and bonus after pre-tax 401(k)/benefits, excluding this vest.

$

Earlier RSU vests and bonuses. Above $1M, withholding jumps to 37%.

%

Your estimated marginal state rate.

%

Many states have a flat supplemental rate; check your vest statement.

Estimated extra tax owed at filing
$2,070.00

Withholding falls about $2,070 short. Consider setting that aside, making an estimated payment, or raising W-4 withholding. Tax year 2026 estimate — not tax advice.

Withheld vs actually owed
WithheldOwed
$0$5,000$10K$15K$20KFederal — Withheld: $16,500Federal — Owed: $18,570FederalState — Withheld: $3,750State — Owed: $3,750State
Vest value (taxable income)
$75,000.00
Federal withheld at vest
$16,500.00
Actual federal tax on the vest
$18,570.00
Federal rate on the vest
24.76%
Your top federal bracket
32%
State withheld
$3,750.00
Estimated state tax on the vest
$3,750.00
Social Security & Medicare on the vest
$3,451.50
Shares sold to cover withholding (approx.)
159
Where the vest value goes
Federal tax: $18,570 (24.8%)State tax: $3,750 (5%)Social Security & Medicare: $3,452 (4.6%)You keep: $49,229 (65.6%)
  • Federal tax$18,57024.8%
  • State tax$3,7505%
  • Social Security & Medicare$3,4524.6%
  • You keep$49,22965.6%
Show the working
  1. Vest value = 500 × $150.00 = $75,000.00
  2. Federal withheld = $75,000.00 × 22% = $16,500.00
  3. Federal tax on $208,900 taxable = $43,304.00; without the vest = $24,734.00
  4. Actual federal tax on the vest = $18,570.00 (24.76%)
  5. State: owed $3,750.00 − withheld $3,750.00 = $0.00
  6. Shortfall = ($18,570.00 − $16,500.00) + ($3,750.00 − $3,750.00) = $2,070.00

Runs entirely in your browser. Nothing you enter is uploaded.

Formula

Vest value = shares × price at vest (taxed as ordinary wages)Withheld = 22% × supplemental wages up to $1M + 37% × the excessActual tax = tax(other income + vest − deduction) − tax(other income − deduction)Shortfall = actual tax − withheld (federal + state)

How it works

When restricted stock units vest, the full market value of the shares becomes ordinary income, exactly like a cash bonus. Your employer must withhold tax, usually by selling some of the shares ("sell to cover") or keeping back shares ("net settlement").

For federal income tax, most employers use the flat supplemental-wage rate: 22% on supplemental pay up to $1 million in the calendar year and 37% on anything above that. The problem is that 22% is often lower than the tax you really owe. If your salary already puts you in the 24%, 32% or 35% bracket, every vested dollar is taxed at that higher rate when you file, and the gap shows up as a balance due in April.

This calculator estimates the true federal tax caused by the vest by computing your 2026 tax with and without it, using the standard deduction for your filing status, and compares that with the 22%/37% withholding. State tax is estimated with a flat rate you enter. It is an estimate, not tax advice: it ignores itemized deductions, credits, other investment income and the Additional Medicare Tax true-up.

Social Security and Medicare are also withheld on RSU income. Social Security stops once your total wages for the year reach the annual wage base, which is why late-year vests for high earners often have less taken out. These payroll taxes are usually withheld correctly, so they are shown but not counted in the shortfall.

Frequently asked questions

Do I pay tax again when I sell the shares?

Only on the change in value after vesting. Your cost basis is the price at vest. If you sell right away there is little or no extra gain; if you hold, the later gain or loss is a capital gain — long-term if held more than a year after vesting.

Can I ask my employer to withhold more?

Some employers let you choose a higher supplemental rate for RSUs. If not, you can raise withholding on your regular paycheck through your W-4, or make quarterly estimated tax payments.

Will I get a penalty for under-withholding?

You generally avoid the federal underpayment penalty if withholding and estimated payments cover at least 90% of this year's tax or 100% of last year's (110% if your prior-year AGI was over $150,000). Large vests can break that, so plan ahead.

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