OPEN-SOURCE SCRIPT

SPY Option returns calculations

This script allows you to calculate returns on double butterfly options, specifically for 0 DTE and 1 DTE(days to expiration) for options that have expiration on Monday, Tuesday and Friday(Mostly SPY). The script is bi-directional, meaning it will calculate the returns on a put and call butterfly simultaneously, not just a put or just a call butterfly. The script was developed to calculate how much return could be made on opening a double butterfly option by opening a position right at the open of the day on a 0 DTE option. The script rounds the price up or down to the nearest strike price at open. From there you would need to chose how far to select your options from the opening strike price. You would also need to select how many contracts you would like to open, negative - is selling an option positive + is buying an option. As an example the script is defaulted to a 0,2,4 strike position with buying 1 contract at the 0, selling 3 contracts at the +/- 2 strike and selling 2 contracts at the +/- strike. The default is set to an unbalanced double butterfly as it allows a better credit collection than a standard butterfly. To change to a standard butterfly change the # of contracts to 1 -2 and 1 respectively.

The script defaults a return of 0 on Tuesdays and Thursdays as there are no 0 DTE options available on those days.
If you have questions about script ask ... if you have questions about options ... the answers will likely take too much time to answer.