RSU Tax Calculator

Enter Calculation

Shares Vested

Fair Market Value per Share ($)

Federal Supplemental Withholding (%)

FICA / Payroll Tax (%)

State Tax Rate (%)

Results

Estimated Tax Withheld at Vest

$17,325

withheld from your vested RSUs

Gross Value at Vest	$50,000
Federal Supplemental Tax	$11,000
FICA / Payroll Tax	$3,825
State Tax	$2,500
Total Effective Rate	34.65%
Net Value After Tax	$32,675

What Is the RSU Tax Calculator?

This calculator applies to the United States. Restricted Stock Units (RSUs) are taxed as ordinary income when they vest. The fair market value of the shares on the vest date is added to your wages, and your employer typically withholds taxes — often by selling some of the shares ("sell to cover"). This tool estimates how much is withheld and what net value you keep. Rates default to the 2024 IRS federal supplemental flat rate (22%) and combined FICA (7.65%), but you can override every rate.

How to Use It

Enter the number of shares that vested, the fair market value (FMV) per share on the vest date, and the three tax rates that apply to you: the federal supplemental withholding rate, the FICA/payroll rate, and your state income tax rate. The calculator multiplies the gross vest value by the sum of these rates to estimate total withholding, then shows your net value after tax.

The Formula Explained

Gross value at vest equals \(\text{Shares} \times \text{FMV}\). The total tax is that gross value times the combined rate, where the combined rate is the federal supplemental rate plus FICA plus state rate. Net value is simply gross value minus the tax.

$$\begin{gathered} \text{Tax at Vest} = G \times \left( \text{Fed \%} + \text{FICA \%} + \text{State \%} \right) \div 100 \\[1.5em] \text{where}\quad G = \text{Shares Vested} \times \text{FMV per Share} \end{gathered}$$

Because RSU income is ordinary income, withholding at the flat 22% supplemental rate can under-withhold for high earners (the rate jumps to 37% above $1M of supplemental wages), so your final tax bill may differ.

Advertisement

At vesting, gross RSU value is split between withholding (federal, FICA, state) and the net value you keep.

Worked Example

Suppose 1,000 shares vest at an FMV of $50, with a federal supplemental rate of 22%, FICA of 7.65%, and state tax of 5%. Gross value = \(1{,}000 \times \$50 = \$50{,}000\). Combined rate = \(22\% + 7.65\% + 5\% = 34.65\%\). Tax withheld = \(\$50{,}000 \times 0.3465 = \$17{,}325\). Net value = \(\$50{,}000 - \$17{,}325 = \$32{,}675\).

Shares × FMV gives gross value; multiplying by the combined rate yields the tax withheld.

FAQ

When are RSUs taxed? At vesting, based on the share price that day — not when you sell. Selling later may trigger separate capital gains tax.

Why is my withholding too low? The 22% flat federal rate may not match your actual marginal bracket, so you might owe more at tax time.

Does this include capital gains? No. This estimates only the income tax withheld at vest. Gains or losses after vest are handled separately when you sell.