RSU Tax Calculator

Free RSU tax calculator. Estimate the federal and state tax attributable to an RSU vest, compare it with common withholding rates, and see how large a gap you may need to plan for. Simplified educational estimate using current federal brackets stacked on top of your annual salary — not tax advice.

What the calculator asks for

Your annual salary or other ordinary income, the value of the RSUs vesting, an estimated state income tax rate, and the withholding rate your plan applies to supplemental wages. Nothing is submitted or stored to produce the estimate.

What the calculator returns

An estimate of the federal tax attributable to the vest, estimated state tax, the amount likely withheld at the rate you select, and the resulting illustrative shortfall or surplus to plan around.

How much tax will I pay on my RSUs?

RSUs are generally taxed as ordinary income at vesting. The fair market value on the vest date is typically added to your wages and taxed at your ordinary rates, plus state income tax where applicable. Holding after vest does not change that ordinary income; it affects only later capital gain or loss, so sell-versus-hold depends on your situation.

Why might withholding not cover the tax?

Employers may withhold on RSU vests using the optional flat-rate method for supplemental wages — 22% up to $1M in a year and 37% above $1M under current federal rules — or using the aggregate method, which can differ. If the rate applied is below your marginal rate, the difference generally becomes due with your return or through estimated payments.

How the withholding gap is calculated

The calculator stacks your vest on top of your annual salary, runs both incomes through progressive federal brackets, takes the difference as an estimate of the federal tax attributable to the vest, adds a simplified state rate, and subtracts the withholding rate you select. The remainder is an illustrative gap, not a tax computation; it ignores payroll taxes, credits, deductions, AMT and local taxes.

What the estimate does not include

Payroll taxes, itemized or standard deductions, credits, AMT, local and city taxes, capital gains on shares held after vest, multi-state allocation, and any employer-specific plan mechanics. Treat the output as a planning range rather than a filing figure, and confirm your numbers with a tax professional.

What to do with the number

A projected shortfall is usually addressed by electing additional withholding where the plan allows, setting aside cash from the vest, or making estimated payments. Which approach fits depends on your safe-harbor position and cash flow.

Related tools and guides

Read how RSUs are taxed at https://samslist.com/how-rsus-are-taxed, estimate single-stock concentration at https://samslist.com/nvidia-stock-concentration-calculator, and compare equity-comp advisors at https://samslist.com/rsu-equity-compensation-advisor.

Want a real plan, not just an estimate?

Book a free intro call with Malcolm Ethridge, a CFP® and IRS Enrolled Agent who specializes in equity comp. Full Sam's List profile and reviews: https://samslist.com/financial-advisor/malcolm-ethridge.

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