RSU Vesting Take-Home Calculator
See what an RSU vest leaves you after the flat 22% supplemental withholding, FICA, and state tax, plus the gap you still owe at filing.
RSU Vesting Take-Home Calculator
Your vest
Enter the vest and your base salary, then pick your filing status, state, and withholding election.
Some stock plans let you elect a higher supplemental rate. Check your plan portal.
Advanced
Earlier vests plus bonuses. Used to apply the $1,000,000 / 37% federal tier mid-year.
Leave blank to assume state withholding matches your state liability.
Enter the shares vesting and the price at vest.
Withheld at vest
Tax actually owed on the vest
No paychecks left this year, so the W-4 route is closed. Use an estimated payment instead.
2026 estimate. Federal tax is modeled on salary plus vest with the standard deduction only, so it excludes other income, itemized deductions, credits, and pre-tax contributions. State tax uses a single flat supplemental rate per state, so it is an estimate rather than per-state bracket math. Not filing-grade.
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Why RSU withholding leaves a gap
When restricted stock units vest, the full market value on the vest date becomes ordinary wages on your W-2. The IRS classifies that value as supplemental wages, the same category as bonuses and commissions, so payroll withholds federal income tax at the flat statutory rate of 22%. Once your cumulative supplemental wages for the year cross $1,000,000, the portion above that line is withheld at a mandatory 37% instead.
The problem is that 22% is a default, not a measurement. Your vest does not sit in isolation; it stacks on top of your salary and is taxed at whatever bracket those last dollars land in. Take a single filer earning $180,000 with a $200,000 vest. Payroll sends $44,000 to the IRS at 22%, but the vest pushes taxable income through the 24%, 32%, and 35% brackets and adds roughly $64,200 of federal tax. That leaves a shortfall of about $20,200, and nothing comes to collect it until April. The bigger your equity relative to salary, the wider it gets.
The four lines that come out of a vest
Federal supplemental withholding is the largest line, but three more follow it. Social Security takes 6.2%, capped at the 2026 wage base of $184,500 of total wages. That cap matters more than most calculators admit: if your salary alone already clears $184,500, the vest carries exactly $0 of Social Security. Medicare takes 1.45% with no cap, plus the 0.9% Additional Medicare surtax. Watch the threshold mismatch there. Your employer applies the surtax above $200,000 of wages from that employer regardless of filing status, while your return uses $250,000 for joint filers, so a married couple in that band is over-withheld on Medicare while being under-withheld on income tax.
State tax is the fourth line, applied at your state's supplemental rate: 10.23% in California, 11.7% in New York, 0% in the nine states with no wage income tax. Add the four together and you get the share math that brings people here. Total withholding divided by the vest-date price, rounded up, is how many shares your employer sells or withholds. That is why 100 vested shares can show up as 60, with a few dollars of rounding residual returned as cash. The same supplemental mechanics drive the Bonus Tax Take-Home Calculator if you have a cash bonus landing in the same year.
Closing the gap before April
There are three practical fixes. The one that works best for most people is extra federal withholding on Form W-4, Step 4(c), which the calculator sizes per paycheck. Payroll withholding is credited as though it were paid evenly across the whole year, so a change made in November can still cure a shortfall created by a February vest. The W-4 Withholding Planner will show you how the change flows through the rest of your paychecks.
A quarterly estimated payment also works, but it is credited on the date you send it, so it cannot repair an earlier quarter. The third option is the blunt one: sell a slice of each vest and park the proceeds. Whichever you choose, aim at a safe harbor: paying in 90% of this year's tax, or 100% of last year's total (110% if your prior-year AGI topped $150,000), keeps you clear of an underpayment penalty. If you are sizing equity inside a job offer rather than reacting to a vest that already happened, the Total Compensation Offer Calculator and the Raise Net Take-Home Impact tool cover that side.
What this tool leaves out
This is a single-vest estimate. It uses one flat state rate rather than per-state brackets, assumes the standard deduction, and looks at one vest instead of your whole year. If you need per-state withholding tables, state items like CA SDI and NY PFL, traditional 401(k) and HSA contributions, year-to-date FICA truncation, or saved profiles for comparing offers, download the Stub44 Salary Calculator app.
Frequently Asked Questions
Common questions about rsu vesting take-home calculator
Why did my employer only withhold 22% on my RSUs?
Because 22% is the statutory flat rate for supplemental wages under IRS Publication 15, not a read on your tax situation. RSU vest income is supplemental, the same bucket as bonuses and commissions, so payroll applies 22% without looking at your salary, your bracket, or your W-4. The rate only changes once your cumulative supplemental wages for the year pass $1,000,000, where the excess is withheld at a mandatory 37%. Below that line you get the same 22% treatment as a coworker earning half your salary.
How much tax will I actually owe on an RSU vest?
Whatever your marginal bracket is once the vest stacks on top of your salary. The vest is ordinary W-2 income, so it lands on the last dollars of your year and is taxed at 24%, 32%, 35%, or 37% for most people with a real equity package. Add Social Security (if you are still under the $184,500 wage base for 2026), 1.45% Medicare, the 0.9% Additional Medicare surtax, and state tax. The calculator above runs the actual 2026 brackets rather than assuming a single rate.
How many shares get sold to cover taxes when my RSUs vest?
Under sell-to-cover or net settlement, your employer takes the total withholding, divides it by the vest-date share price, and rounds up. At a 22% federal rate plus FICA and a high state rate, that routinely lands between 30% and 45% of the grant, which is why 100 vested shares can arrive as 60. The rounding residual comes back as a small cash amount on your paycheck. Switch the calculator to shares mode to see your own split.
Can I ask my employer to withhold more than 22% on RSUs?
Sometimes. A minority of stock plans let you elect a higher supplemental rate (commonly 27%, 32%, or 37%) through the equity portal, and the calculator lets you model each one. Most payroll systems only offer the flat 22%, though. The fix that works everywhere is extra federal withholding on Form W-4, Step 4(c), which you can size with the W-4 Withholding Planner.
Do RSUs pay Social Security and Medicare tax?
Yes, RSU vest income is wages for FICA. Social Security is 6.2% but only up to the 2026 wage base of $184,500, so if your salary alone already clears that, the vest carries no Social Security at all. Medicare is 1.45% with no cap, plus the 0.9% Additional Medicare surtax. Note the mismatch there: your employer starts the surtax at $200,000 of wages from that employer regardless of filing status, while your return uses $250,000 for joint filers.
Will I owe an underpayment penalty if my RSU withholding falls short?
Not automatically. You avoid the penalty by hitting a safe harbor: paying in at least 90% of the current year tax, or 100% of last year total tax (110% if your prior-year AGI was over $150,000). There is also no penalty if the balance due is under $1,000. A large vest early in the year is the risky case, since the shortfall sits unpaid for months. The estimated payment figure above shows the size of the exposure.
Should I fix the gap with W-4 withholding or quarterly estimated payments?
W-4 withholding is usually the better tool. Payroll withholding is treated as paid evenly across the year no matter when it happened, so bumping Step 4(c) in November can cure a shortfall created by a February vest. Estimated payments are credited on the date you make them, so a late one does not repair an earlier quarter. Use the per-paycheck figure above if you have paychecks left, and the single estimated payment only if you do not.
Are RSUs taxed twice, at vest and again at sale?
No. The vest-date value is ordinary income on your W-2, and that same value becomes your cost basis. If you sell immediately, gain is near zero and there is nothing more to pay. If you hold, only the appreciation above that basis is a capital gain. The common trap is broker reporting: many 1099-B forms show a $0 or unadjusted basis, so you have to correct it on Form 8949 or you really will pay twice.