Hi there. I've created a small non commercial web calculator for bellows calculations. I know other copies of this exist already, my intention was to make something really concise for field use. It's set up as a progressive web app, so you can install it to your phone like an app for offline (field) usage.

Mods, please move or remove if this is the wrong spot for this!

Calculator
https://exposure-buddy.rjyoung.ca/

Code
https://github.com/bobbotron/expo-assist