Vesting Calculator

Vesting is how employees and founders earn equity over time instead of receiving it all on day one. A common US startup schedule is four-year vesting with a one-year cliff: no shares vest until the first anniversary, then 25% vests at the cliff and the remainder vests in equal monthly installments over the next 36 months. If you leave before the cliff, you typically forfeit unvested shares.

Stock options and RSUs each have different tax and exercise rules, but the vesting timeline concept is similar. Your grant agreement controls cliff length, vest period, acceleration on change of control, and what happens after termination. This calculator models linear monthly vest after the cliff — it does not replace your cap table or legal documents.

Example: 48,000-share grant, 1-year cliff, 4-year total vest. At 18 months after grant: 25% (12,000 shares) vested at the cliff plus 6 months of the remaining 36 months (6/36 × 36,000 = 6,000) = 18,000 vested, 30,000 unvested. Actual plans may round to whole shares or use daily accrual.

Founders often negotiate the same four-year pattern as employees, but founder shares may vest from company formation rather than a hire date. Early employees sometimes receive accelerated vesting on acquisition — single-trigger (all unvested vests) or double-trigger (vesting accelerates only if you are terminated after the deal). Your grant letter specifies which applies.

Monthly vesting after the cliff means each month unlocks an equal slice of the post-cliff pool. With a 48,000-share grant and 36,000 shares remaining after the cliff, each month releases 1,000 shares. Some companies round down until a full share accumulates; others use fractional share tracking internally.

Unvested shares or options usually disappear when you resign voluntarily. Involuntary termination without cause may trigger partial acceleration depending on the plan. Layoffs, acquisitions, and IP disputes are where vesting terms matter most — read the section on termination and change of control in your agreement.

ISOs, NSOs, and RSUs can share identical vest calendars but diverge sharply at tax time. RSUs typically create W-2 income when shares vest. Options may not trigger tax until exercise. This tool counts shares only; it does not estimate AMT, withholding, or 83(b) elections.

Worked example at month 30: same 48,000-share grant. Cliff at month 12 released 12,000 shares. Months 13–30 are 18 monthly installments of 1,000 shares each = 18,000 additional vested shares. Total vested = 30,000; unvested = 18,000 with 18 months left on the schedule.

Compare your output to Carta, Pulley, or your offer letter spreadsheet before making financial plans. Vesting math here is educational — legal ownership depends on board approvals, exercise windows, and company repurchase rights.

Board approval dates, grant dates, and hire dates can differ — vesting usually starts on a defined vesting commencement date in your grant notice, not necessarily your first day of work.

Acceleration clauses are negotiated, not automatic. Founders and early executives sometimes receive partial or full acceleration; junior employees rarely do unless a tender offer or acquisition triggers double-trigger terms.

When comparing offers, ask for grant size, strike price, vesting start date, cliff length, and post-termination exercise window. A larger grant with a one-year cliff still yields zero vested equity if you leave at month eleven.

International employees may receive different grant types (non-qualified options, local stock plans) with vest calendars that mirror US patterns but different tax withholding — local payroll rules apply at vest.

Refresh grants and promotion grants stack as separate awards with their own cliffs and schedules — total vested shares is the sum across active grants, not one blended schedule.