RSU Tax Calculator 2026 — Withholding Gap & Vesting Tax
Calculate tax owed when your RSUs vest. See federal, state, FICA taxes, and the critical withholding gap — how much extra you may owe at filing time.
Shares that vest in this event
$
Fair market value (FMV) on the vesting date $
Your base salary and other wages this year (before RSU) %
CA: 9.3%+, NY: 6.85%+, WA/TX/FL: 0% Leave 0 to auto-calculate at 22% flat rate; or enter actual shares withheld
Common vesting amounts:
$0
Vesting Value (Gross Income)
$0
Total Estimated Tax
$0
Company Withheld (22% flat)
$0
Withholding Gap (You Owe More)
Tax Component Breakdown
| Tax Component | Calculation | Amount |
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How to Use This RSU Tax Calculator
Enter the number of shares vesting and the share price at vesting (the FMV on the vesting date, from your brokerage confirmation or equity platform). Enter your other W-2 income so the calculator can determine your true marginal rate. The "shares withheld" field defaults to auto-calculating at 22% — leave it at 0 to see the standard employer withholding, or enter the actual number of shares withheld by your employer.
The Formula
Vesting Value = Shares Vesting × FMV at Vesting
Federal Tax = Marginal Rate on (Other Income + Vesting Value − Standard Deduction)
Federal Withholding = min(Vesting Value, $1,000,000) × 22% + max(0, Vesting Value − $1,000,000) × 37%
SS Tax = min(Other Income + Vesting Value, $184,500) × 6.2% − SS Already Paid
Medicare = Vesting Value × 1.45% + max(0, Total Income − $200,000) × 0.9%
Withholding Gap = Total Tax − Company Withheld
Federal Tax = Marginal Rate on (Other Income + Vesting Value − Standard Deduction)
Federal Withholding = min(Vesting Value, $1,000,000) × 22% + max(0, Vesting Value − $1,000,000) × 37%
SS Tax = min(Other Income + Vesting Value, $184,500) × 6.2% − SS Already Paid
Medicare = Vesting Value × 1.45% + max(0, Total Income − $200,000) × 0.9%
Withholding Gap = Total Tax − Company Withheld
Example
500 RSUs vest at $150/share, $120,000 other W-2 income, Single, CA 9.3%:
Vesting value: 500 × $150 = $75,000 (added to W-2 income)
Total income: $195,000 | Taxable: $180,000 | Marginal rate: 32%
Federal tax on RSU: $75,000 × ~32% = ~$24,000 (actual varies by bracket)
Employer withholds at 22%: $75,000 × 22% = $16,500
Withholding gap: ~$7,500 — owed at filing | CA state: $75,000 × 9.3% = $6,975
Total RSU tax: ~$31,000+ (check net shares you actually receive)
Vesting value: 500 × $150 = $75,000 (added to W-2 income)
Total income: $195,000 | Taxable: $180,000 | Marginal rate: 32%
Federal tax on RSU: $75,000 × ~32% = ~$24,000 (actual varies by bracket)
Employer withholds at 22%: $75,000 × 22% = $16,500
Withholding gap: ~$7,500 — owed at filing | CA state: $75,000 × 9.3% = $6,975
Total RSU tax: ~$31,000+ (check net shares you actually receive)
Extended
RSU Vesting Schedule Planner
Model quarterly vesting events, cumulative tax impact, and sell-to-cover vs net shares comparison
Model up to 4 quarterly vesting events and see cumulative tax impact, withholding gaps, and sell-to-cover comparison across the year.
| Vest Date | Shares | Price | Gross Value | Estimated Tax | Employer Withheld | Gap |
|---|
Sell-to-Cover vs Net Shares (Current Vesting Event)
| Method | Shares Received | Cash Received | Tax Withheld | Expected Gap at Filing |
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Frequently Asked Questions
How are RSUs taxed when they vest?
RSUs (Restricted Stock Units) are taxed as ordinary income at vesting — the fair market value of the shares on the vesting date is added to your W-2 income. Your employer typically withholds federal income tax at the 22% supplemental wage rate (37% above $1 million), plus Social Security and Medicare (FICA). If your marginal tax rate is higher than 22%, you will likely owe additional tax at filing time.
Why is there a withholding gap with RSU taxes?
The IRS requires employers to withhold on RSU vesting at the supplemental wage rate of 22% (or 37% above $1M). But if your total income puts you in the 24%, 32%, or 35% bracket, the 22% withholding rate is not enough. The "withholding gap" is the difference between what your employer withheld and what you actually owe — this amount is due at tax time. Many tech workers are surprised by a large tax bill because of this gap.
What is the difference between withholding at 22% vs my actual rate?
The IRS sets a flat 22% supplemental withholding rate for W-2 employees (as of 2026). This is the default rate your employer uses for bonus and RSU income. However, your actual marginal rate depends on your total income. If your W-2 wages plus RSU vesting value puts you in the 24%, 32%, or higher bracket, you will owe the difference at tax time. For high-income tech workers, this gap can reach $10,000–$50,000+ per vesting event.
What is "sell to cover" vs "net shares" for RSU tax withholding?
"Sell to cover" means your employer sells enough shares to cover the tax withholding at vesting — you receive fewer shares but owe less at filing. "Net shares" (cash withholding) means shares are retained and you receive a check reduction from payroll. Either way, the withholding is typically at the 22% supplemental rate, which may not cover your full tax liability. The gap analysis in this calculator shows how much you may still owe.
Do RSU shares have a cost basis for future capital gains?
Yes. When RSUs vest, the fair market value on the vesting date becomes your cost basis for future capital gains purposes. If you sell the shares later at a higher price, you owe capital gains tax on the gain above the vesting price. If you sell immediately at vesting (same-day sale), there is typically no additional capital gains — only the ordinary income tax at vesting. Holding the shares for over 1 year after vesting converts future appreciation to long-term capital gains (0%, 15%, or 20%).