What the workbook does

Restricted stock units are taxed as ordinary income when they vest, and most employers withhold a flat 22% on that income. Stacked on top of a salary the same dollars are usually taxed at 24%, 32%, 35% or 37%, so a balance builds toward April. The free calculator shows the size of that gap for one year. This workbook shows it for every grant, every vest and every year through 2030 — and what it would take, per quarter or per paycheck, to reach the federal safe harbor.

Eight sheets

  • Setup — filing status, salary and growth, pre-tax deductions, planning date, state rates, prior-year tax for the safe-harbor alternative, default share price, selected year.
  • Grants — up to 20 grants: shares, first vest, frequency, number of vests, optional price override.
  • Vest Schedule — every vest: date, shares, income, federal withholding at 22% (37% over the $1 million supplemental line, tracked cumulatively), state, Social Security to the wage base, Medicare and Additional Medicare by payroll rule, shares sold to cover, net shares delivered, and each vest’s share of the year’s gap.
  • Tax Year Summary (2026–2030) — taxable income, federal tax by bracket, tax on the RSU slice and its effective rate, what payroll withholds, the federal and state gap, the 90% and prior-year safe-harbor tests, additional payments that would reach them, and a per-paycheck W-4 Step 4(c) equivalent.
  • Quarterly Plan — the selected year’s safe-harbor amount as four equal installments against cumulative withholding, with the April 15 / June 15 / September 15 / January 15 due dates.
  • Dashboard — the year’s shortfall, effective rate, withheld vs. owed chart by year, next vest, and employer-stock concentration shown as a fact.
  • Instructions and a hidden _Lists sheet holding every rate and bracket, with its source.

Built on verified parameters

Federal brackets and standard deductions are tax-year-2026 values from IRS Rev. Proc. 2025-32; the 22% and 37% supplemental rates, the $184,500 Social Security wage base and the Medicare rates are from Publication 15 (2026). The release build is recalculated in LibreOffice and checked against the same worked examples the free calculator publishes — $180,000 of salary plus $120,000 of vests produces $36,200.25 of tax on the RSU slice, $26,400 withheld, and a $9,800.25 gap.

What it does not do

Other income, credits, the Alternative Minimum Tax, ESPP or stock options, head-of-household or married-filing-separately brackets, and the annualized-income installment method. It does not tell you whether to sell, hold or cover shares. Educational estimate, not tax, legal or investment advice — work with a qualified tax professional for decisions.