Taxes10 min readUpdated Jun 2026

RSU vesting: how to plan for the tax bill

Why RSUs are taxed as ordinary income, how supplemental withholding works and what most employees get wrong at vest.

What This Guide Covers

This page turns the topic into a decision process: what to measure, which assumptions matter, where the answer can flip, and which calculator to use for your own numbers.

Taxes

Decision Framework

Step 1

Start with taxable income, not gross income. Deductions, filing status, benefit elections, and timing determine the rate that actually applies.

Step 2

Separate federal, payroll, state, local, and withholding effects. A good tax plan usually comes from identifying which layer is driving the bill.

Step 3

Use estimates for planning, then verify final filing details with current forms, software, or a qualified tax professional.

Key Takeaways

Define the decision this guide is solving before comparing options: Why RSUs are taxed as ordinary income, how supplemental withholding works and what most employees get wrong at vest.
Use your own numbers instead of rules of thumb. Defaults are useful for orientation, but the answer usually changes with income, time horizon, tax rate, debt cost, or location.
Save a calculator scenario after reading so the assumptions are visible when you come back later.

Before You Decide

Write down the current baseline.
Run the conservative case.
Change one assumption at a time.
Record the point where the answer changes.
Separate withholding from actual liability and confirm current-year rules before filing.