FINANCIAL · EMPLOYEE STOCK OPTION
Employee Stock Option Calculator
Estimate your net proceeds from exercising ISO or NSO stock options — enter strike price, current FMV, sale price, and tax rates to see exercise cost, AMT (ISO), ordinary income tax (NSO), capital gains tax, and net profit. Consult a CPA before exercising.
About This Calculator
Calculate the net proceeds from exercising ISO (Incentive Stock Option) or NSO (Non-Qualified Stock Option) grants. Enter the number of shares, strike price, current fair market value, expected sale price, and your marginal tax rates to see the exercise cost, tax at exercise (AMT for ISO, ordinary income for NSO), capital gains tax at sale, and net profit. Stock option tax is complex — this is a simplified federal estimate for planning only.
How It Works
For ISOs: no ordinary income tax at exercise (no W-2 income), but the bargain element (FMV minus strike, times shares) creates an Alternative Minimum Tax (AMT) preference item — a potential additional tax at 28%. If you meet holding periods (2+ years from grant, 1+ year from exercise), all gain at sale is taxed at long-term capital gains rates. Disqualifying dispositions (holding periods not met) convert the gain to ordinary income. For NSOs: the bargain element is ordinary income at exercise (subject to income tax and FICA withholding). Appreciation above FMV at sale is capital gain — long-term if held 1+ year from exercise, short-term otherwise.
The Formula
Net Proceeds = Sale Proceeds − Exercise Cost − Total Tax
- Exercise Cost
- Strike price × number of shares (cash you pay to exercise)
- Bargain Element
- (Current FMV − Strike Price) × shares — the in-the-money spread
- AMT Exposure
- ISO only: Bargain Element × 28% (simplified AMT estimate)
- Ordinary Tax
- NSO only: Bargain Element × your marginal ordinary income rate
- Capital Gains Tax
- Appreciation above FMV (NSO) or total gain (ISO qualifying) × LTCG or STCG rate
Frequently Asked Questions
- What is the difference between ISO and NSO?
- ISOs (Incentive Stock Options) can only be granted to employees and have potential preferential tax treatment — qualifying dispositions pay only long-term capital gains, not ordinary income, at sale. However, the spread at exercise triggers AMT. NSOs (Non-Qualified Stock Options) can be granted to anyone (employees, consultants, board members) and are simpler — the spread at exercise is ordinary income; only appreciation above the FMV at exercise is capital gain.
- What is the Alternative Minimum Tax (AMT)?
- The AMT is a parallel tax system with fewer deductions. The ISO bargain element is an AMT preference item — it increases your Alternative Minimum Taxable Income (AMTI). If your calculated AMT exceeds your regular income tax, you pay the AMT instead. This calculator uses a simplified 28% rate as a conservative estimate; your actual AMT depends on your total AMTI, the AMT exemption amount, and other factors.
- What are the ISO holding period requirements?
- To qualify for long-term capital gains treatment on an ISO, you must hold the shares for more than 2 years from the grant date AND more than 1 year from the exercise date. Selling before these periods is a "disqualifying disposition" — the spread at exercise (or profit at sale, whichever is less) becomes ordinary W-2 income.
- Should I exercise ISOs and hold, or exercise and sell?
- This depends on your AMT situation, the stock's risk profile, and your cash position. Exercising and holding qualifies you for LTCG treatment but concentrates your wealth in one stock and creates AMT risk. Exercising and immediately selling (a "same-day sale" or "disqualifying disposition") avoids AMT but converts the gain to ordinary income. A CPA or financial advisor can model the full after-tax impact for your situation.
- Is the AMT credit recoverable?
- Yes. AMT paid on ISO exercises creates an AMT credit (Form 8801) that can be used to offset regular income tax in future years when your regular tax exceeds your AMT. The credit is often fully recoverable over time, but the timing depends on your income trajectory.