Your RSU vest
Used to calculate your marginal tax bracket
• 2026 federal brackets • 2026 SS wage base $184,500
• Assumes standard deduction (itemizing may change results)
• State rates are simplified marginal rates; CA 13.3% applies >$1M
$4,548 owed at filing
Your employer withholds 22% federal but your marginal rate is 32.0%. Set aside $4,548 for your federal tax bill.
Tax breakdown
32.0% marginal rate
9.3% rate
Up to $184,500 wage base
No wage cap
Income exceeds threshold
39.9% of vest value
Employer withholding
Federal withheld (22% flat)
$22,000
Federal you actually owe
$26,548
What is RSU Tax Calculator?
When restricted stock units (RSUs) vest, the fair market value of the shares becomes ordinary income — taxed just like salary. The catch: your employer withholds at a flat 22% federal rate (the IRS supplemental wage rate), but if your marginal tax bracket is 32%, 35%, or 37%, you will owe significantly more at tax time. This calculator computes your full federal, state, and FICA tax on a vest event and shows the exact withholding gap you need to cover.
How to Use
- Enter the number of shares vesting and the price per share on the vest date.
- Enter your other ordinary income for the year (salary, freelance income, etc.) to correctly calculate your marginal bracket.
- Select your filing status and state of residence.
- The calculator shows federal marginal rate, state tax, FICA, total tax, and the withholding gap.
- Use the "Amount to set aside" figure to make a quarterly estimated tax payment.
Why Use This Tool?
Tips & Best Practices
- Pay the withholding gap as estimated taxes the same quarter your RSUs vest (Q1: Apr 15, Q2: Jun 15, Q3: Sep 15, Q4: Jan 15)
- If you sell shares immediately at vest, your capital gain/loss is zero — no capital gains tax
- California (SDI) and New York (NYC local tax) have additional taxes not shown; consult a CPA for these
- If your company allows supplemental withholding elections, ask HR to increase the withholding rate above 22%
- Use the 2026 Social Security wage base ($184,500) — if your salary already exceeds this, you owe no SS on RSU income
Frequently Asked Questions
How are RSUs taxed when they vest?
When RSUs vest, the fair market value (shares × price on vest date) is treated as ordinary income — it is added to your W-2 and taxed at your marginal federal income tax rate, plus state income tax and FICA. Your employer withholds at the 22% IRS supplemental rate for federal. If your real marginal rate is higher, you owe the difference at filing.
What is the RSU withholding gap?
The withholding gap is the difference between the 22% your employer withholds and your actual marginal federal rate. For example, at a 35% marginal rate on a $100,000 vest, the gap is $13,000. This becomes due when you file your tax return unless you pay estimated taxes during the year.
Do I pay Social Security tax on RSUs?
Yes, unless your total wages (salary + RSU income) already exceed the 2026 Social Security wage base of $184,500. If your salary is $200,000, your RSU income has no additional Social Security tax, but still has Medicare (1.45%) and possibly the Additional Medicare surtax (0.9%).
What happens when I sell my vested RSU shares?
Your cost basis is the fair market value at vest. Selling immediately = no capital gain. Holding 12+ months before selling = long-term capital gains rates (0%, 15%, 20%). Holding less than 12 months = short-term capital gains at ordinary income rates. The NIIT (3.8%) also applies to capital gains for high earners.