Stock Option Value Calculator
Calculate ESO value across exit price scenarios.
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How It Works
Enter strike price, current FMV, growth rate, years to expiry, risk free rate, and volatility. The tool values your employee stock options. Strike comes from your grant letter. FMV is the latest 409A or public market price. Volatility and risk free rate should reflect current market conditions and company stage. Refresh inputs after each funding round when 409A reprices your grant. Enter grant strike, current fair market value, and vested versus unvested shares separately when modeling departure scenarios. Split vested and unvested in grant table when modeling departure forfeit versus exercise decision. Enter grant strike, current fair market value, and vested versus unvested shares separately when modeling departure scenarios. Split vested and unvested in grant table when modeling departure forfeit versus exercise decision.
Review current option value, intrinsic and time value, exit scenarios at multiple prices, and break even exit price for your options. Compare scenario tables across grant years if you hold multiple tranches. Unvested shares are not exercisable but scenario analysis helps evaluate job offer equity packages before accepting. Early exercise of ISOs within 90 days of departure preserves favorable tax treatment worth modeling separately. Tender offers and secondary transactions may occur at discounts to the last 409A FMV used here. Compare intrinsic value today against Black Scholes time value when deciding early exercise before IPO lockup ends. Early exercise for ISO starts AMT clock: model tax cash separately from exercise cost. Compare exercise today versus wait for next 409A mark when illiquidity discount is wide. Compare intrinsic value today against Black Scholes time value when deciding early exercise before IPO lockup ends. Early exercise for ISO starts AMT clock: model tax cash separately from exercise cost. Compare exercise today versus wait for next 409A mark when illiquidity discount is wide.
against Black Scholes time value when deciding early exercise before IPO lockup ends. Early exercise for ISO starts AMT clock: model tax cash separately from exercise cost. Compare exercise today versus wait for next 409A mark when illiquidity discount is wide. Compare intrinsic value today against Black Scholes time value when deciding early exercise before IPO lockup ends. Early exercise for ISO starts AMT clock: model tax cash separately from exercise cost. Compare exercise today versus wait for next 409A mark when illiquidity discount is wide.
Use Stock Option Value Calculator whenever inputs change: after market moves, new contributions, or revised personal assumptions. Bookmark the page for quick reruns without installing software.
Step by step
- Enter strike, FMV, growth, expiry, rate, and volatility
- Review current option value and exit scenarios
- Adjust volatility and time to see value impact
Worked example
Enter strike price, current FMV, growth rate, years to expiry, risk free rate, and volatility. Enter the sample inputs described in How it works to reproduce the scenario step by step.
Adjust one input at a time to see sensitivity. Stock Option Value Calculator updates instantly so you can stress test optimistic and conservative assumptions before acting.
When to use this calculator
Reach for Stock Option Value Calculator when calculate eso value across exit price scenarios.. It suits quick what if analysis before trades, allocation changes, or plan updates.
Pair with related tools when the decision spans taxes, liquidity, or multi year projections beyond what one formula captures.
Common mistakes
Copying outputs without checking input units or stale market prices is a frequent error with Stock Option Value Calculator. Confirm tickers, percentages, and dates before acting.
Running a single baseline scenario ignores tail risks. Stress test with conservative inputs and compare against related tools listed below when the decision is material.
The Formula
Option Value = S×N(d1) - K×e^(-rT)×N(d2) where d1 = (ln(S/K) + (r + σ²/2)T) / (σ√T), d2 = d1 - σ√T. Intrinsic = max(S-K, 0). Time Value = Option - Intrinsic. Break Even = K + Option Value.
Black Scholes call pricing with polynomial CDF approximation. Exit scenarios from 0.5× to 5× strike. Does not model vesting cliffs, early exercise, 409A valuations, or tax at exercise. Use for planning conversations with financial advisors. RSU grants have no time value component and require a different valuation approach entirely. Private company FMV is board determined 409A: public stock uses market price; illiquidity discount not applied here. Liquidity discount on private shares often twenty to thirty percent below last round price. 83b election deadline thirty days after early exercise: missing deadline taxes vesting spread at ordinary rates. AMT on ISO exercise can exceed cash from selling some shares: plan tax liquidity. Private company FMV is board determined 409A: public stock uses market price; illiquidity discount not applied here. Liquidity discount on private shares often twenty to thirty percent below last round price. 83b election deadline thirty days after early exercise: missing deadline taxes vesting spread at ordinary rates. AMT on ISO exercise can exceed cash from selling some shares: plan tax liquidity.
Limitations and assumptions
Black Scholes call pricing with polynomial CDF approximation. Exit scenarios from 0.5× to 5× strike. Does not model vesting cliffs, early exercise, 409A valuations, or tax at exercise. Use for planning conversations with financial advisors. RSU grants have no time value component and require a different valuation approach entirely. Private company FMV is board determined 409A: public stock uses market price; illiquidity discount not applied here. Liquidity discount on private shares often twenty to thirty percent below last round price. 83b election deadline thirty days after early exercise: missing deadline taxes vesting spread at ordinary rates. AMT on ISO exercise can exceed cash from selling some shares: plan tax liquidity. Private company FMV is board determined 409A: public stock uses market price; illiquidity discount not applied here. Liquidity discount on private shares often twenty to thirty percent below last round price. 83b election deadline thirty days after early exercise: missing deadline taxes vesting spread at ordinary rates. AMT on ISO exercise can exceed cash from selling some shares: plan tax liquidity. Stock Option Value Calculator does not replace personalized advice. Fees, slippage, account specific rules, and behavioral constraints may change real world outcomes.
Key terms
- How is ESO value calculated
- The tool uses Black Scholes to compute the theoretical option value: Call = S×N(d1) - K×e^(-rT)×N(d2).
- What exit scenarios are shown
- Eight scenarios: 0.
- Model assumption
- Time value is highest when stock is near the strike and plenty of time remains.
Compare alternatives
Equity Dilution Simulator models cap table impact alongside employee option pools. Use those calculators when stock option value calculator alone does not capture the full decision.
Internal links on portfolios.tools help you chain calculators: run Stock Option Value Calculator first, then validate edge cases with a specialized tool from the related section below.
FAQ
How is ESO value calculated?
The tool uses Black Scholes to compute the theoretical option value: Call = S×N(d1) - K×e^(-rT)×N(d2). Intrinsic value = max(S-K, 0). Time value = option value - intrinsic value. ESOs are call options on company stock with vesting schedules not modeled here. Use current fair market value as S and your grant strike as K. Private company 409A valuations update quarterly and directly shift option value before IPO. AMT on ISO exercise without sale can create large tax bill: model cash needed to hold shares past exercise date. Intrinsic value equals max of zero and fair market value minus strike times share count for vested portion. AMT on ISO exercise without sale can create large tax bill: model cash needed to hold shares past exercise date. Intrinsic value equals max of zero and fair market value minus strike times share count for vested portion.
What exit scenarios are shown?
Eight scenarios: 0.5×, 0.75×, 1×, 1.25×, 1.5×, 2×, 3×, 5× the strike price. Each shows option value, intrinsic value, and time value at that exit price. The 2× and 5× scenarios help founders and early employees estimate upside at successful exit multiples. Deep out of the money grants show mostly time value until FMV approaches strike. IPO lockup periods delay liquidity even when exit price scenarios look attractive on paper. NSO exercise triggers ordinary income on spread at exercise: withholding on paycheck may not cover full liability. NSO exercise triggers ordinary income on spread at exercise: withholding on paycheck may not cover full liability.
When is time value highest?
Time value is highest when stock is near the strike and plenty of time remains. Deep in the money options have near zero time value. Deep out of the money have low option value overall. Volatility input should reflect company stage: early startups use 40 to 60%, public companies 25 to 35%. Longer expiry increases time value at all moneyness levels. Post IPO volatility often compresses as lockup expiry approaches and float increases. Post termination exercise window of ninety days is common: unvested shares forfeited unless company offers extended window. Ninety day post termination exercise window is common: unvested shares forfeit on departure. Post termination exercise window of ninety days is common: unvested shares forfeited unless company offers extended window. Ninety day post termination exercise window is common: unvested shares forfeit on departure.
What is the break even exit price?
Break Even Exit = Strike Price + Current Option Value. You must sell at or above this price to cover both the strike cost and the current option premium. For ISO grants break even ignores AMT impact which can be substantial at exercise. NSO exercise triggers ordinary income on the spread at exercise. Secondary market sales before IPO may occur below break even if FMV is discounted for illiquidity. RSU vests taxed as ordinary income at vest with no strike: different tool than ESO grant math. RSU vests taxed as ordinary income at vest with no strike: different tool than ESO grant math.
How do assumptions affect option value?
Adjust growth rate, volatility, years to expiry, and risk free rate. Higher volatility and longer expiry increase option value. Growth rate affects projected FMV at future exit but Black Scholes uses current FMV as input. Risk free rate typically tracks 10 year Treasury yield. Small volatility changes move option value significantly for at the money grants. Compare ISO versus NSO tax treatment separately since exercise timing affects net proceeds not captured here. Net exercise options reduce cash needed at exercise but increase share count dilution at the company level. Tender offers before IPO let employees sell secondary: compare tender price to modeled FMV in this tool. Secondary tender at discount to preferred price still beats zero if company delays IPO indefinitely. Tender offers before IPO let employees sell secondary: compare tender price to modeled FMV in this tool. Secondary tender at discount to preferred price still beats zero if company delays IPO indefinitely.
Can I use Stock Option Value Calculator on a phone or tablet?
Yes. Stock Option Value Calculator runs entirely in your mobile browser with the same formulas as desktop. Optional localStorage may remember inputs on your device when enabled in browser settings.
Where is my data stored when I use Stock Option Value Calculator?
Nowhere on our servers. Calculations execute locally in your browser. Optional localStorage saves form fields on your device only and never transmits portfolio numbers over the network.
Should I rely on Stock Option Value Calculator for tax or legal decisions?
No. Stock Option Value Calculator provides educational math only. Tax law, account rules, and personal circumstances vary. Consult a qualified tax or legal professional before transactions with material consequences.
Related Tools
Equity Dilution Simulator models cap table impact alongside employee option pools. Risk Reward Ratio helps evaluate liquid public holdings separately from illiquid ESO wealth. Post Retirement Tax covers exercise timing and AMT considerations not modeled here. Wash Sale Alert flags tax loss harvesting conflicts when exercising and selling employer stock. Equity Dilution Calculator shows how later funding rounds shrink grant percent even when strike stays fixed. Equity Dilution Calculator shows how later funding rounds shrink grant percent even when strike stays fixed.