Here is a link to an IGT Calculator for Adventure. To edit, you can copy the sheet to your google drive by going to File > Make a copy and choosing "My Drive" as a folder. From there you should be able to edit the page. Let me know if this doesn't work but from my testing it seems to work great!!!

https://docs.google.com/spreadsheets/d/1QM8glVDN2nGDn9sdm3qImF_xW8awOhbX/edit?usp=sharing&ouid=101318267660157683732&rtpof=true&sd=true