Black-Scholes Options Pricing
Calculator

European-style call and put pricing, implied volatility, and Greeks. An educational Black-Scholes-Merton lab for finance students and self-taught options learners — not investment advice, not a broker, and not a DLOM or WACC toolkit.

✓ Call & Put Prices ✓ Implied Volatility Solver ✓ Delta · Gamma · Theta · Vega · Rho ✓ Payoff Diagrams ✓ Put-Call Parity
Step 1: Enter Your Option Parameters

Input the five required variables: stock price (S) — the current market price; strike price (K) — the exercise price; time to expiration (T) in years (e.g., 0.25 for 3 months); risk-free rate (r) — typically a matching Treasury yield; and implied volatility (σ) — the annualized expected movement. Optionally enter a dividend yield (q).

Step 2: Read the Results

The calculator instantly shows the theoretical call and put price, plus all five Greeks: Delta, Gamma, Theta (per day), Vega (per 1% vol), and Rho (per 1% rate).

Step 3: Solve for Implied Volatility

Know the market price but not the IV? Scroll to the Implied Volatility Solver, enter the observed price, select call or put, and the Newton-Raphson solver will find the volatility that matches.

Step 4: Visualize the Payoff

The Payoff Diagram charts profit and loss at expiration across stock prices, accounting for the premium paid. Toggle between long call, long put, or both.

Step 5: Check Put-Call Parity

Enter observed call and put market prices with the same strike and expiry to verify whether the fundamental pricing relationship holds. Deviations may signal mispricings.

Important Notes

This calculator uses the generalized Black-Scholes-Merton model supporting continuous dividend yield. It assumes European-style exercise, constant volatility, and log-normal returns. All calculations run entirely in your browser — no data is transmitted.

Inputs
$
Must be greater than 0
$
Must be greater than 0
yrs
0.08 ≈ 1mo · 0.25 = 3mo · 0.5 = 6mo · 1 = 1yr
Must be greater than 0
%
0%20%
%
0%100%
Must be greater than 0
%
0%10%
Results
Call Price
—
Long call option
Put Price
—
Long put option
Option Greeks
GreekCallPutMeaning
Δ Delta——Price sensitivity to S
Γ Gamma——Delta sensitivity to S
Θ Theta——Price decay per day
V Vega——Sensitivity to vol (1%)
ρ Rho——Sensitivity to rate (1%)

Implied Volatility Solver

Enter an observed market price for a call or put option. The solver uses Newton-Raphson iteration to reverse-engineer the implied volatility. Uses the same S, K, T, r, q inputs from above.

$
Enter a market price and click solve to find the implied volatility.

Option Payoff Diagram

Visualize profit and loss at expiration. Uses the current S, K, and calculated premiums from the calculator above.

About the Black-Scholes Model

The Black-Scholes model (1973) provides a closed-form solution for pricing European-style options. It assumes the underlying asset follows geometric Brownian motion with constant volatility.

Core Formulas

C = S·e-qT·N(d₁) − K·e-rT·N(d₂)
P = K·e-rT·N(−d₂) − S·e-qT·N(−d₁)

C = Call price, P = Put price, N() = cumulative normal distribution

d₁ and d₂

d₁ = [ln(S/K) + (r − q + σ²/2)T] / (σ√T)

d₂ = d₁ − σ√T

σ = volatility, T = time in years, r = risk-free rate, q = dividend yield

Input Parameters

S = Current stock price
K = Strike price
T = Time to expiry (years)
r = Risk-free interest rate
σ = Implied volatility
q = Continuous dividend yield

Model Assumptions

European-style exercise only
Constant volatility over life
Log-normal returns distribution
No arbitrage opportunity

Put-Call Parity Checker

Enter observed market prices for a call and put with the same strike and expiry to check if parity holds.

C + K·e-rT  =  P + S·e-qT

Uses the same S, K, T, r, q inputs from the calculator above.

$
$
Enter market call and put prices above to run the parity check.

Frequently Asked Questions

What is the Black-Scholes model?
The Black-Scholes model (1973) is a mathematical framework for pricing European-style options. It uses five inputs — stock price, strike price, time to expiration, risk-free rate, and implied volatility — to calculate the theoretical fair value of call and put options.
What are the Greeks in options trading?
The Greeks measure an option's sensitivity to various factors: Delta measures price sensitivity to the underlying stock, Gamma measures the rate of change of Delta, Theta measures time decay per day, Vega measures sensitivity to volatility changes, and Rho measures sensitivity to interest rate changes.
How do you calculate implied volatility?
Implied volatility is calculated by reverse-engineering the Black-Scholes formula. Given the market price of an option, you solve for the volatility that makes the Black-Scholes price equal the observed market price. This is done numerically using iterative methods like Newton-Raphson, since there is no closed-form solution.
What is put-call parity?
Put-call parity is a fundamental relationship: C + K·e^(-rT) = P + S·e^(-qT). It states that the price of a call plus the present value of the strike must equal the put price plus the stock price adjusted for dividends. Violations may indicate arbitrage opportunities.