RSU Withholding Shortfall

Find out if your RSU withholding rate is actually covering your real tax bill, or if April will surprise you.

RSU vest value this year (gross) $120,000

Employer withholding rate on RSUs 22%

Your true marginal bracket 35%

State tax rate 9%

April shortfall

Additional tax owed beyond withholding

Total tax withheld

True tax liability

RSU vest: withheld vs true tax

💡 Shortfall insight

RSU Tax Withholding Shortfall Calculator

The RSU Tax Withholding Shortfall Calculator catches the most common surprise in any equity-heavy compensation package. You enter the gross value of your RSU vests this year, the rate your employer withholds at (typically 22 percent on supplemental income), your real marginal federal bracket, and your state tax rate. The calculator returns the dollars actually withheld, your true tax liability, and the April shortfall you will owe if those two diverge. Use it the day a meaningful vest hits. The flat 22 percent withholding rate routinely under-covers anyone in the 32 percent bracket or higher, and missing the shortfall by tax day triggers underpayment penalties on top of the unpaid amount.