RSU Vesting Tax Withholding Calculator
Check whether the tax withheld on your vesting RSUs covers what you will owe.
Runs in your browser. Your files never leave your device. See how to check
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How to do it
- 1Step 1: Open RSU Vesting Tax Withholding Calculator and add your input
Type your numbers or text, add your file, or pick the options you need. Nothing is uploaded: everything stays in your browser.
- 2Step 2: What RSU Vesting Tax Withholding Calculator does
Check whether the tax withheld on your vesting RSUs covers what you will owe.
- 3Step 3: Read the result and compare
The result appears at once. Change one value to see how the answer moves, then keep the figure that fits your case.
- 4Step 4: Copy or save it
Copy the result or download it. For an important decision, confirm it with the official source or an adviser.
About this tool
Enter the shares that vest, the share price, your other income and the withholding rate your employer uses. The calculator works out the extra federal income tax the vest really causes, the FICA and state tax, the shares an employer would keep for net settlement and the shortfall or surplus against your actual tax.
Why there is often a shortfall
Employers usually withhold federal income tax on RSUs at the 22% supplemental rate. If the vest pushes you into the 24%, 32% or 35% bracket, the real tax is higher and the difference is due when you file. Above $1 million of supplemental wages the withholding rate is 37%.
How the real tax is found
The vest is added on top of your other taxable income (after the standard deduction) and the tax on the extra amount is taken from the federal brackets. Social Security tax stops at the wage base, Medicare tax is 1.45%, and 0.9% extra applies above $200,000 of wages for single filers.
What is not included
State tax is a flat rate you enter. Gains after vesting, alternative minimum tax and the timing of sales are outside this tool.
Worked example
500 shares vest at $120 ($60,000) for a single filer with $200,000 of other income in 2026: the extra federal tax is $17,770 but 22% withholding is $13,200, a shortfall of $4,570. With FICA of $1,410 and 6% state tax of $3,600 the total tax is $22,780, or 38% of the vest, and an employer keeping shares for tax would hold back about 152 shares.
Tips for best results
Check every box before you rely on a result, because one wrong digit changes the whole answer. Use the exact figures from your payslip, bill, certificate or contract, and keep a note of the date you calculated. Rates, thresholds and rules change from time to time, so for tax, fees and legal matters treat the output as an estimate and confirm with the official source named on this page. You can run as many scenarios as you like; nothing is saved or sent, and refreshing the page clears the boxes.
Quick facts
- Category: UK & US
- Works in your browser, no sign-up, no upload.
- Your input stays on your device.
- Available in English.
- Content last reviewed:
Frequently asked questions
Why was only 22% withheld?
That is the flat supplemental rate. It does not look at your total income, so higher earners are usually under-withheld.
Can I ask for more withholding?
Some employers let you choose a higher rate or sell more shares. Otherwise make estimated tax payments or raise your W-4 withholding.
Are RSUs taxed again when I sell?
Only on the gain or loss after vesting. The value at vesting is already counted as wages and becomes your cost basis.
What is net share settlement?
The employer keeps enough shares to pay the withholding and gives you the rest, so you do not have to sell any yourself.