Options payoff calculator

Enter the underlying, strike, time, rate, dividend yield and volatility. You get the Black-Scholes-Merton price and five Greeks for the call and the put with the put-call parity check, then up to four legs priced leg by leg and their payoff at expiry across forty-one prices. Same logic as the Bindler workbook, verified against it.

Pricer

Underlying priceStrikeTime to expiry, years Risk-free rate, continuous, %Dividend yield, continuous, %Volatility, annual, %

Strategy: up to four legs on the same underlying and expiry

Contract multiplierGrid: lowest price at expiryGrid: step between prices

Leg	Type	Side	Strike	Contracts	Premium per unit, your fill

Leave a leg's strike or contracts blank to ignore it. Premium is per unit of underlying; the multiplier scales it to money. Each leg is also priced by the model at its own strike so the model value can be compared with what you paid.

The workbook: Pricer, Strategy and the expiry gridOptions P&L and Greeks Workbook, $19: the pricer with parity, four legs priced by the model and by your fill, forty-one expiry prices with every leg, P&L, max profit and max loss, and a Guide. Verified through a formula engine before listing.

See the workbook

Method: Black-Scholes-Merton for European options with a continuous dividend yield. Vega is per volatility point, theta per calendar day (365), rho per rate point. The normal CDF uses a series for small arguments and a continued fraction for large ones, checked against a reference to better than 1e-9. Payoff at expiry is intrinsic value per leg times contracts times the multiplier, less the net premium paid. American exercise, volatility skew, transaction costs and margin are outside this page. Same logic as the Bindler workbook. A model on your inputs, not a market, and not investment advice.