RSU Vesting Schedule Tax Planner (2026)

Your RSU grant is a fixed number of shares — but the tax bill changes every year the stock moves. This planner projects your federal and state tax on RSU income across a full 4-year vesting schedule, shows the withholding gap each year, and tells you how much to set aside quarterly. Enter your Year 1 vest value and an assumed annual stock growth rate to see how your total tax exposure evolves.

Why your RSU tax bill grows when the stock does

Most RSU grants specify a fixed number of shares per vesting period, not a fixed dollar value. If your company granted 2,000 shares per year and the stock was at $150 when the grant was made, your Year 1 vest is $300,000. If the stock reaches $165 by Year 2, the same 2,000 shares vest at $330,000 — an additional $30,000 of ordinary income. At a combined federal and California marginal rate near 50%, that extra $30,000 produces roughly $15,000 more in taxes.

Multiply this across four years at a consistent growth rate and the compounding becomes significant. A $300K Year 1 grant growing at 15% per year generates over $1.5M in cumulative RSU ordinary income across the full schedule — with each later year carrying a higher absolute tax burden because the vest value is larger and the marginal rate is still at the top bracket.

The quarterly estimated tax math

The IRS expects taxes to be paid throughout the year as income is earned, not all at once in April.² If your total withholding falls short, you owe an underpayment penalty — calculated at the federal short-term interest rate plus 3 percentage points (roughly 7–8% annualized in 2026). The standard way to avoid this is Form 1040-ES quarterly estimated tax payments, or additional W-4 withholding.

The IRS safe harbor rules let you avoid penalties entirely if you pay either:

• 110% of your prior-year tax liability (100% if prior-year AGI was $150,000 or less), or
• 90% of your current-year actual tax liability

For most high-income tech employees with unpredictable RSU income, the 110% prior-year anchor is the safest and most predictable approach. The quarterly payment column above shows the amount needed to cover the gap each year assuming equal quarterly installments — but if you use the prior-year safe harbor, your required payments are based on last year's return, not this projection. See the full mechanics in our RSU estimated tax payments guide, including 2026 quarterly due dates.

Strategies to reduce the gap as vests compound

The withholding gap isn't fixed — these levers reduce it before Year 4 arrives:

• Adjust your W-4. You can request additional flat-dollar federal withholding per paycheck using W-4 Step 4(c). Spreading extra withholding across regular paychecks avoids a quarterly lump-sum payment. California's DE-4 and New York's IT-2104 allow the same. See the W-4 RSU adjustment guide for the exact calculation.
• Mega backdoor Roth contributions. After-tax 401(k) contributions reduce your taxable income. In 2026, the § 415(c) total defined-contribution limit is $72,000; after the $24,500 elective deferral, you may have up to $47,500 in after-tax headroom (employer match dependent) to contribute and convert tax-free. See the mega backdoor Roth guide.
• Donate appreciated RSU shares. RSU shares held for at least 12 months after vest can be donated to a donor-advised fund at full fair market value — generating a deduction without recognizing a gain. In a high-vest year, a $50K donation to a DAF reduces your AGI by $50K, potentially dropping you one bracket. See the charitable giving guide for how the math works at $400K+ AGI.
• Loss harvesting from prior RSU lots. If you held RSU shares that declined after vest, harvesting those losses offsets ordinary income up to $3,000 per year (with unlimited carry-forward against future gains). See the wash sale + RSU guide to understand how quarterly vest dates create acquisition traps.
• 10b5-1 plan for systematic diversification. A pre-arranged sell schedule set up during an open trading window lets you sell regularly throughout the year — spreading the gain recognition and tax impact rather than letting concentration build. See the 10b5-1 plans guide.

What this calculator doesn't model

This planner shows the income-tax withholding gap. It does not account for:

• AMT from ISO exercises. If you also hold ISOs (common at pre-IPO companies or in mixed-package grants), exercising and holding can trigger a separate AMT liability on top of RSU ordinary income. See the ISO AMT calculator.
• NIIT on post-vest appreciation. RSU income at delivery is ordinary income — not subject to the 3.8% Net Investment Income Tax. But if you hold vested shares and they appreciate before you sell, the subsequent gain is investment income subject to NIIT above $200K AGI (single) or $250K AGI (MFJ).³ See the sell vs. hold decision guide.
• Year-over-year salary and bonus changes. This model holds base compensation constant. If your salary increases 5–10% annually alongside stock growth, your marginal rate exposure accelerates faster than the table shows.
• Itemized deductions. High mortgage interest, large charitable giving, or significant state and local taxes may let you itemize — increasing your deduction above the standard amount and reducing your effective rate.
• State residency changes. Moving from California to Washington or Texas during the vesting period eliminates state income tax on future vests, but California still asserts a claim on income allocated to pre-move work under its workday-sourcing rules. See the RSU state taxes guide.

For a plan that accounts for all of these variables simultaneously — coordinated across four years of vesting — an equity-comp specialist builds a year-by-year model specific to your grant schedule, income trajectory, and likely life events.