This app was mentioned in 2 comments, with an average of 3.00 upvotes
Sounded a bit like what I remember of Ruhlman's Ratio app that sadly has been abandoned for 8 years.
https://play.google.com/store/apps/details?id=com.ruhlman.droid.Ratio&hl=en
So I went through the store and there are a few sourdough ratio apps out there. Good luck with yours.
https://play.google.com/store/search?q=sourdough+ratios&c=apps
Hijacking your top comment to say, There's an app for that too. https://play.google.com/store/apps/details?id=com.ruhlman.droid.Ratio