RSU Tax Withholding Gap Planner

Project the tax you actually owe on vested stock versus the supplemental withholding your employer remits. Enter the total RSU value, your company's withholding rate, and your blended marginal rate. Add state or local surtaxes if applicable to surface any shortfall, quarterly catch-up targets, and refund potential.

Gross market value of restricted stock units scheduled to vest within the calendar year.
Federal supplemental rate or the rate your company applies when selling RSUs for taxes.
Blend your expected federal bracket, FICA exposure, and other marginal taxes.
Defaults to 0%. Add your combined state, local, or city tax rate if RSU income is taxable there.

This planner estimates income tax only and does not account for AMT, NIIT, timing differences, or other credits. Consult a tax professional for personalized planning.

Examples

  • $180,000 vest, 22% withholding, 37% marginal, 0% state ⇒ Total liability is $66,600.00, withholding covers $39,600.00, leaving a $27,000.00 shortfall. Set aside $6,750.00 quarterly or $2,250.00 monthly to avoid penalties.
  • $95,000 vest, 24% withholding, 32% marginal, 5% state ⇒ Combined tax due is $35,150.00, withholding remits $22,800.00, so plan for a $12,350.00 gap. Reserving $3,087.50 quarterly or $1,029.17 monthly keeps cash ready for April filings, including $4,750.00 of state tax.

FAQ

Should I include payroll taxes in the marginal rate?

Yes. Add the employee-side Social Security and Medicare percentages that still apply to your income so the shortfall captures every mandatory contribution.

How do I treat RSUs delivered in multiple tranches?

Add the total fair market value you expect to vest across all tranches during the tax year so the gap reflects the cumulative withholding imbalance.

What if I already made estimated tax payments?

Subtract those payments from the shortfall before scheduling new quarterly deposits. The calculator isolates the gap between RSU withholding and liability; you can net in other tax credits manually.

Can I split the catch-up between payroll and quarterly payments?

Yes. Request additional withholding on regular paychecks to cover part of the gap and schedule the remainder as Form 1040-ES estimated payments. The planner shows the total dollars you need to distribute.

Additional Information

  • Calculations assume RSU income is fully taxable in the vest year and taxed at the marginal rates you provide.
  • State and local percentages default to 0% to mirror employers that only withhold at the federal supplemental rate.
  • Quarterly and monthly reserve targets divide the projected shortfall evenly across the remaining quarters or months in the year.
  • If the employer withholding exceeds your marginal rate, the planner estimates an overpayment that should appear as a refund at filing.

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