Option Price Calculator
Updated: June 2026
Enter a price, strike, time to expiry, volatility and interest rate, and this free Black-Scholes calculator returns the option’s theoretical value plus its five Greeks — delta, gamma, theta, vega and rho — for both calls and puts. Everything is computed live in your browser; nothing is sent to a server.
Black-Scholes calculator
Edit the inputs — the theoretical price and Greeks update as you type.
Theta is shown per day; vega and rho per 1% change in volatility and rate. European exercise, no dividends.
What the Black-Scholes model does
The Black-Scholes model turns five observable inputs into a single fair value for a European option. It answers the question every option trader starts with: given today’s price, how much should this call or put actually be worth?
The output is a theoretical price — a benchmark. Compare it with the market price to see whether an option looks rich or cheap, and read the Greeks to understand how that value will move as the stock, time and volatility change.
The five inputs explained
Underlying price is the current price of the stock or ETF. Strike is the price at which the option can be exercised. Days to expiry is how long the option has left — the model converts it to a fraction of a year.
Volatility is the annualised standard deviation of the underlying’s returns, in percent — the single most important and most uncertain input. The risk-free rate is the short-term interest rate; it barely matters for near-dated options and more for long-dated ones.
What the Greeks tell you
Delta is how much the option price moves for a $1 move in the stock. Gamma is how fast delta itself changes. Theta is the daily time decay — what the option loses each day, all else equal. Vega is the change in price for a one-point move in volatility, and rho for a one-point move in the interest rate.
Here theta is shown per day and vega and rho per 1% change, which is how traders normally read them.
Assumptions and limits
Black-Scholes prices European options — exercisable only at expiry — and assumes constant volatility, no dividends and frictionless trading. Real American options, dividend-paying stocks and volatility skew all cause small differences from the model price.
Treat the number as a well-founded estimate, not a guarantee. For live implied volatility, real option chains and the probability of profit on an actual position, use the full calculator.
Want live prices, implied volatility and probability of profit?
Frequently asked questions
What is a Black-Scholes option price calculator?
It computes the fair value of a European call or put from five inputs — underlying price, strike, time to expiry, volatility and the risk-free rate — using the Black-Scholes formula, along with the option’s Greeks.
Is this option price calculator free?
Yes, completely free and with no signup. It runs entirely in your browser, so the numbers you type never leave your device.
What volatility should I enter?
Use the option’s implied volatility if you have it, or a historical volatility estimate for the underlying. Price is most sensitive to this input, so it is worth getting close. The full calculator reads implied volatility from live option chains for you.
Does it work for both calls and puts?
Yes — switch the option type and the price and Greeks update for a call or a put.
Why does the model price differ from the market price?
Black-Scholes assumes constant volatility, no dividends and European exercise. Real markets price in volatility skew, dividends and early-exercise value, so the market and model prices rarely match exactly — the gap itself is information.
About Us · Careers · For brokers · Contact · Methodology · Disclaimer · Privacy Policy · Cookie Policy (EU) · Terms & Conditions · Security · Home