Free stock option calculator
Calculate stock option intrinsic value and profit — enter strike price, current stock price, premium paid, and number of contracts, updated live, as you type.
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ROI = (gain − cost) ÷ cost × 100. This is simple ROI and does not account for time value of money.
Results are estimates. Consult a professional.
How the stock option calculator works
A stock option is a contract giving the buyer the right — but not the obligation — to buy (call) or sell (put) 100 shares of a stock at a fixed price (the strike price) before or on the expiration date. The buyer pays a premium upfront for this right. The calculator focuses on the intrinsic value and profit/loss at expiration for both call and put options.
At expiration, an option's value collapses to its intrinsic value — how far it is 'in the money'. For a call option, intrinsic value is the amount the stock price exceeds the strike price. For a put option, it is the amount the strike price exceeds the stock price. Subtract the premium paid to get net profit or loss per share.
Worked example: call option with a $50 strike on a $65 stock
Sam buys a call option on a stock with a $50 strike price, paying a $3 premium per share ($300 per contract). At expiration the stock is trading at $65. Sam exercises the option, buying 100 shares at $50 and immediately selling at $65.
Call option profit/loss at expiration
The table below shows the profit or loss per contract (100 shares) for a call option with a $50 strike price and a $3 premium at various stock prices at expiration. Positive figures are profits; negative figures (capped at −$300) are losses.
| Stock Price at Expiration | Intrinsic Value / Share | Profit (Loss) / Share | Profit (Loss) / Contract |
|---|---|---|---|
| $40 | $0.00 | −$3.00 | −$300 |
| $50 | $0.00 | −$3.00 | −$300 |
| $53 | $3.00 | $0.00 | $0 (breakeven) |
| $60 | $10.00 | $7.00 | $700 |
| $65 | $15.00 | $12.00 | $1,200 |
| $75 | $25.00 | $22.00 | $2,200 |
Source: Options profit formula — intrinsic value minus premium paid. Strike price $50, premium $3. One contract = 100 shares. Loss capped at premium paid; gains theoretically unlimited.
Tips for evaluating stock options
Options are flexible instruments but come with unique risks. Master these concepts before putting capital at risk.
- Time decay works against buyers — Options lose extrinsic (time) value every day, accelerating toward expiration. Even if a stock moves in your favour, time decay can erode your profit. Buyers need the stock to move quickly and sufficiently.
- Implied volatility affects premium cost — High implied volatility inflates option premiums. Buying options before earnings announcements, for example, often means paying a premium that collapses after the event (a 'volatility crush') even if the stock moves in your direction.
- Define your maximum loss before entering — For option buyers, the maximum loss is always the premium paid. Know this dollar amount before buying. For option sellers (covered calls, cash-secured puts), the risk profile is very different and potentially much larger.
- Calculate breakeven before you buy — For a call, the stock must rise above strike + premium just to break even at expiration. For a $50 strike with a $3 premium, you need the stock above $53 — a 6% move if currently at $50.
- Consider 'in the money' vs 'out of the money' options — In-the-money options (where intrinsic value already exists) cost more but have a higher probability of expiring with value. Out-of-the-money options are cheaper but require a larger stock move to profit.
Accuracy and limitations
This calculator computes intrinsic value and profit or loss at expiration only. It does not model time value, implied volatility, the Greeks (delta, gamma, theta, vega), early exercise of American-style options, or multi-leg strategies such as spreads, straddles, or iron condors. Real options prices before expiration include extrinsic value and can differ substantially from intrinsic value alone. For live options pricing, use a broker platform that displays the full option chain with real-time Greeks.
Not financial advice — consult a financial professional for your specific situation.
Key stock options terms
About this stock option calculator
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