What this employee stock options calculator measures
Estimate the positive spread of an ISO or NSO, or the share value of an RSU grant, using a USD reference price. The calculator shows annual vesting milestones and seven hypothetical prices. It does not calculate option time value, employer-grant fair value, or the amount you can legally exercise today.
Enter the grant terms before comparing scenarios
- Enter a ticker for an available U.S. listing quote, or supply a verified USD reference price. A manual price overrides the quote request and can represent a private-company assumption. It does not establish fair market value.
- Choose ISO, NSO, or RSU and enter total shares, grant date, vesting years, and the cliff. For options, also enter strike price and expiration years. The model rejects an option whose entered expiration date has passed.
- Choose federal and state rate assumptions. These rates are added and applied uniformly; the tool does not determine your tax bracket from income or filing status.
- Calculate, then distinguish the vested summary from the whole-grant scenario table. Changing grant inputs clears the previous result. Adjust growth only to explore an assumption, not a forecast.
Intrinsic value and cash required are different
Option spread per share is max(reference price − strike price, 0). Multiplying by modeled vested shares gives the vested intrinsic value. Exercise cost is strike price × shares; that is cash required to acquire shares, not an additional deduction from a spread that already subtracts the strike. RSUs have no exercise price. Neither a zero spread nor an unvested grant proves an option has no potential future value.
For example, 100 vested options with a $20 strike and a $30 share price have $1,000 of intrinsic value and a $2,000 exercise cost. A hypothetical combined rate of 30% produces a $300 deduction and $700 modeled net gain. This assumes exercise and immediate sale at $30, without fees or other taxes; it is not a tax estimate for holding the shares.
How the annual vesting model works
Before the cliff, no shares vest. At the cliff, the model catches up to that year’s cumulative fraction; subsequent grant anniversaries add the next portion. Cumulative shares are rounded down to whole shares, with the final anniversary reaching the grant total. A February 29 anniversary is clamped to February 28 in non-leap years. There is no monthly vesting, acceleration, forfeiture, or termination window model.
Vested shares are counted using the current UTC date. Future milestone prices compound the reference price by the entered growth rate over the remaining time. Past milestones use the current reference price as a comparison basis, not a reconstructed historical price or past taxable value.
Tax boundaries for ISOs, NSOs, and RSUs
For options, the numerical tax scenario assumes exercise and immediate sale at the same price. For ISOs this is a disqualifying disposition, not a qualifying long-term capital-gains sale. For NSOs it models the ordinary-income spread, under the common assumption that the option had no readily determinable fair market value at grant. RSU scenarios assume settlement and sale occur together at the modeled price; actual settlement and tax timing can differ.
ISO exercise-and-hold may create an AMT adjustment. That adjustment is not the same as AMT owed, which depends on the broader tax return. The calculator therefore does not present spread × 28% as AMT. Payroll taxes, NIIT, deductions, credits, progressive brackets, withholding, and later capital gains or losses are outside this model.
Consult the grant agreement for transfer restrictions, exercise windows, and settlement conditions. A public quote does not guarantee a permitted sale, and a private-company valuation does not guarantee liquidity.
U.S. tax references: IRS stock option tax overview, Form 6251 instructions on ISO adjustments, and Publication 525 on compensation and restricted property. Use current rules and qualified advice for an actual transaction.