Introduction
This option price calculator helps you find the fair value of call and put options. Just enter a few numbers — the stock price, strike price, time to expiration, volatility, interest rate, and dividend yield — and the tool does the math for you. It uses the Black-Scholes model for European options and a binomial tree model for American options. You get the option price, all five Greeks (Delta, Gamma, Vega, Theta, and Rho), a payoff chart, and a full step-by-step breakdown of every calculation. You can also look up a stock ticker to pull in a live price automatically.
Whether you are learning how options work or checking a trade idea, this calculator gives you clear results in seconds. All fields update in real time, so you can adjust any input and see how it changes the price right away. If you want to explore the Black-Scholes formula in more detail, try our dedicated Black Scholes Calculator.
How to Use Our Option Price Calculator
Enter details about a stock option below to get its fair price, Greeks, a payoff chart, and a full step-by-step solution for both call and put options.
Option Style: Pick European or American. European options can only be used on the expiration date. American options can be used at any time before they expire.
Ticker Symbol (optional): Type a stock ticker like AAPL or SPY and click Fetch. This fills in the current stock price for you. You can skip this and type the price yourself.
Underlying Price (S): Enter the current price of the stock or asset the option is based on. Use the number box or drag the slider.
Strike Price (K): Enter the price at which the option lets you buy or sell the stock. This is set when the option contract is created.
Days Until Expiration (T): Enter how many calendar days are left until the option expires. You can also pick a date from the date picker instead. Need help figuring out how many days remain? Our Days Until Calculator can help.
Volatility (σ): Enter the expected annualized volatility as a percent. This measures how much the stock price is likely to swing. A higher number means bigger expected moves. Volatility is closely related to the standard deviation of a stock's returns.
Risk-Free Rate (r): Enter the annualized interest rate on a safe investment like a U.S. Treasury bill. This is shown as a percent. If you want to compare this to other yield benchmarks, our Bond Yield Calculator can help.
Dividend Yield (q): Enter the stock's annual dividend yield as a percent. If the stock pays no dividend, leave this at zero. You can find a stock's yield with our Dividend Yield Calculator.
Results update as you change any input. You can also click Calculate to refresh or Reset to Defaults to start over. Use the toggles above the chart to view payoff diagrams and Greek curves for long or short call and put positions.
What Is an Option Price Calculator?
An option is a contract that gives you the right to buy or sell a stock at a set price before a certain date. A call option lets you buy. A put option lets you sell. You pay a price called the premium to own that right. This calculator helps you figure out what that premium should be based on math, not guesswork. Once you know the fair price, you can estimate potential profits using our Options Profit Calculator or model broader trade outcomes with the Options Calculator.
How Option Prices Are Calculated
This tool uses two proven pricing models. For European options, which can only be used on the expiration date, it uses the Black-Scholes model. This formula relies on the cumulative normal distribution and a natural logarithm of the stock-to-strike ratio. For American options, which can be used at any time before expiration, it uses the Binomial Tree (CRR) model. Both are standard methods used by traders and investors around the world.
Key Inputs That Affect Option Prices
Five main inputs determine what an option is worth:
- Underlying Price (S) — The current price of the stock. Tracking how that price changes over time is key to gauging potential gains; our Stock Profit Calculator can help you model stock-level returns.
- Strike Price (K) — The price at which you can buy or sell the stock through the option.
- Time to Expiration (T) — How many days are left until the option expires. More time usually means a higher price.
- Volatility (σ) — How much the stock price tends to swing up and down. Higher volatility raises the option price. Volatility is derived from the variance of historical returns.
- Risk-Free Rate (r) — The interest rate on safe investments like Treasury bills. The way this rate compounds over time is similar to the logic behind our Compound Interest Calculator.
Understanding the Greeks
The Greeks are numbers that tell you how sensitive an option's price is to changes in the inputs above. Delta shows how much the option price moves when the stock moves $1. Gamma shows how fast Delta itself changes. Theta tells you how much value the option loses each day as time passes. Vega measures the effect of a change in volatility. Rho measures the effect of a change in interest rates. Together, the Greeks help traders understand and manage risk. If you are sizing a position based on how much risk each Greek implies, our Position Size Calculator is a useful companion tool.
Intrinsic Value vs. Time Value
Every option price is made up of two parts. Intrinsic value is the profit you would get if you used the option right now. Time value is the extra amount you pay for the chance that the option could become more profitable before it expires. As expiration gets closer, time value shrinks. This is called time decay. Understanding this concept is closely related to how the Present Value Calculator discounts future cash flows — the less time remaining, the less a future payoff is worth today.
Moneyness: ITM, ATM, and OTM
Options are grouped by how the stock price compares to the strike price. An option is in the money (ITM) if using it right now would be profitable. It is at the money (ATM) if the stock price and strike price are about equal. It is out of the money (OTM) if using it right now would not be profitable. This status affects both the price and the risk of the option. Knowing whether a trade breaks even is essential — our Break Even Calculator can help you analyze that threshold across different scenarios, and the ROI Calculator lets you measure overall return on any investment.