Equity Compensation

Stock Option Calculator (ISO/NSO)

Estimate the value and tax impact of your stock options with ISO vs NSO comparison

Quick Answer:ISOs can save you significant taxes if you meet holding period requirements. NSOs are taxed as ordinary income at exercise. Use this calculator to compare both scenarios and plan your exercise strategy.

Option Details

Number of Options

Strike Price ($)

Current/Expected Share Price ($)

Option Type

Vesting Period (years)

Federal Tax Rate (%)

Capital Gains Rate (%)

State Tax Rate (%)

Net Gain After Tax

Calculating... after exercise and taxes

Spread Per Share

Total Spread (Pre-Tax Gain)

Exercise Cost

Estimated Tax Owed

Total Value at Current Price

Tax Rate Applied

Visual Comparison

Total Value$0

Exercise Cost$0

Tax Owed$0

Net Gain$0

Expert Insight 2026 Pro Tip

For ISOs, consider exercising early in the tax year to start the holding period clock. If you can hold shares for at least 1 year after exercise and 2 years after the grant date, your gains qualify for long-term capital gains rates instead of ordinary income rates -- potentially saving you 9-17% in taxes. Watch out for AMT implications when exercising ISOs with large spreads.

Frequently Asked Questions

What is the difference between ISO and NSO stock options?

ISOs (Incentive Stock Options) receive favorable tax treatment if held for at least 1 year after exercise and 2 years after grant -- the gain is taxed at long-term capital gains rates. NSOs (Non-Qualified Stock Options) are taxed as ordinary income at exercise on the spread between strike price and fair market value, plus applicable payroll taxes. ISOs are only available to employees, while NSOs can be granted to contractors and advisors as well.

When should I exercise my stock options?

The optimal exercise timing depends on several factors: your current tax bracket, expected stock price trajectory, expiration date, and whether you hold ISOs or NSOs. Early exercise of ISOs can start the clock on qualifying disposition holding periods. Consider exercising when you believe the stock is undervalued or when approaching expiration. For NSOs, spreading exercises across tax years can help manage your tax bracket.

Do I owe taxes when my stock options vest?

No, vesting alone does not trigger a tax event for stock options. Taxes are triggered at exercise (when you buy shares at the strike price). For NSOs, the spread is taxed as ordinary income at exercise. For ISOs, there is no regular income tax at exercise, but the spread may be subject to Alternative Minimum Tax (AMT). This is different from RSUs, which are taxed at vesting.