Hi!
I've made a google sheet from scratch for this :) check tab QFE and Cooridnates. Spent all winter vacation on it haha.
I can make it for external use, maybe. As of now this is a link to the sheet i personally use. It automatically does just about everything for you. Gets the altitude from google maps, calculate the qfe. All you need to provide is temp and qnh at sea level, + coordinates in DEC format (DD.MM,MM)
https://docs.google.com/a/tryggheimstrand.no/spreadsheets/d/1WU9NxfpYSeZSEnekXMaALiUsiuB6fzrcfD_-OMfmaBc/edit?usp=drivesdk