Stock Option Exercise Cost & Tax Calculator

Calculate exactly what it costs to exercise your stock options and what you\'ll owe in taxes. Make informed decisions about when to exercise and hold vs sell.

Number of stock options to exercise

Exercise price per option (what you pay to buy)

Current market price of the stock

How long you've held since exercise (affects tax rate)

Your marginal federal + state income tax rate

Long-term capital gains rate

Cashless exercise (sell to cover) or hold shares

Spread = (Current Price - Strike Price) × Options\nExercise Cost = Strike Price × Options\nTax (NSO) = Spread × Income Tax Rate\nTax (ISO Long-term) = Spread × Capital Gains Rate\nTax (ISO Short-term) = Spread × Income Tax Rate\nNet Profit = Spread - Tax
10,000 options @ $5 strike, stock at $25\nHolding > 1 year, Cap gains rate 20%\n\nSpread = ($25 - $5) × 10,000 = $200,000\nTax = $200,000 × 20% = $40,000\nNet Profit = $200,000 - $40,000 = $160,000\nROI = $160K / $50K cost = 320%

What is the difference between ISO and NSO stock options?

ISOs (Incentive Stock Options) get favorable tax treatment: no tax at exercise if held, but AMT may apply. Tax only at sale (long-term gains if held >1 year). NSOs (Non-Qualified Stock Options) are taxed as ordinary income at exercise on the spread. Choose ISOs when possible for tax efficiency.

How are stock options taxed?

NSO taxation: Spread = Ordinary Income at exercise, taxed at your income rate. ISO taxation: No regular tax at exercise, but AMT may apply. At sale: if held >1 year after exercise and >1 year after grant = long-term capital gains. If sold earlier = ordinary income.

What is a cashless exercise?

Cashless exercise (sell-to-cover) is when you sell enough shares immediately to cover the exercise cost and taxes. You receive remaining shares or cash. Example: 100 options, $5 strike, $25 current = $2,500 cost, $2,500 spread. Sell ~107 shares ($5+tax) to cover, keep rest.

When should I exercise my stock options?

Exercise when: (1) Stock price significantly exceeds strike (in the money), (2) You need liquidity, (3) Company might go public soon, (4) Options expire soon. Consider holding if: (1) Company has high growth potential, (2) You can afford taxes without selling, (3) Long-term hold for capital gains treatment.

What is the holding period requirement for ISOs?

To get long-term capital gains treatment on ISOs: hold shares for >1 year AFTER EXERCISE and >1 year after GRANT. You can exercise and hold until sale. If sold too early, gains become ordinary income. Example: Exercise Jan 2024, sell March 2025 = long-term. Exercise Jan 2024, sell Dec 2024 = ordinary income.

What is AMT for stock options?

AMT (Alternative Minimum Tax) may apply to ISO exercises. The spread at exercise counts as AMT preference item. If your regular tax would be less than AMT, you may owe the difference. You get AMT credit carryforward to offset future taxes. Consult tax professional - AMT can be significant with large ISOs.

What is the break-even price for exercising options?

Can I exercise options without selling shares?

Yes - "exercise and hold" - you pay strike price, receive shares, and hold them. You owe ordinary income tax (ISO = potential AMT) on the spread at exercise. Then you can hold for long-term capital gains treatment. This requires cash to pay exercise cost and taxes upfront.