ThetifyOptions selling calculator
Sell a cash-secured put, write a covered call or open a put credit spread. Every number below is computed in your browser from the inputs you type, by the same pricing engine as the Thetify app. There is no market data here and nothing is filled in for you.
Sell one cash-secured put: you collect the premium and agree to buy 100 shares at the strike.
Prices use Black-Scholes at your IV. Probabilities and the expected value use a lognormal model at your HV. Per share; no dividends, fees or early assignment.
Solving IV from a premium you saw, the model-versus-history fat-tail chart and three seller decision tools are in the Thetify app.
Coming soon to iPhone and Android. The app is in final testing.
What the readings mean
- Probability of profit (POP): The modelled chance the position is above water at expiration, under the scenario’s own assumptions.
- Probability ITM at expiry: The modelled chance the option is in the money at the moment it expires.
- Probability of touch: The modelled chance the stock reaches the strike at some point before expiration, not only at the end.
- Breakeven: The stock price at expiration where the position comes out flat: strike minus premium for a short put.
- Expected value (EV): The average outcome per share if this same trade were repeated across the whole modelled distribution.
Full definitions are in the glossary. How the numbers are made
Cash-secured put calculator · Covered call calculator · Put credit spread calculator