About VestWiz

VestWiz is a free set of tax estimators built for US employees with equity comp who receive equity compensation — RSUs, incentive stock options, and ESPP shares.

Equity comp creates some of the most expensive and most misunderstood tax situations in personal finance: flat 22% withholding that doesn't match your marginal rate, AMT bills on ISO exercises with no cash to pay them, and ESPP cost-basis errors that lead to double taxation. These calculators exist to surface those problems before they become April surprises.

How the numbers work

Every calculator on this site reads its tax figures — brackets, rates, caps, thresholds — from a single, clearly commented data file that is updated each January for the new tax year. The current figures reflect tax year 2026.

Tax methodology reviewed by [credential — e.g., CPA/EA name and designation].

Privacy by design

There is no account, no server, and no database. Every calculation runs locally in your browser; your salary, share counts, and results never leave your device. Read the full privacy policy.

What this site is not

These are estimates, not advice. Equity situations get complicated fast — multi-state moves, disqualifying dispositions, AMT credit carryforwards — and a qualified tax professional (CPA or Enrolled Agent) is worth the fee when real money is on the line.