This app was mentioned in 1 comment, with an average of 1.00 upvote
Thanks for the suggestion. I may add in-app purchase to remove ads. FYI - I have another app (Strength Tracker - $0.99) that allows you to log and track 1RM. It also shows your progress against a strength standard.
https://play.google.com/store/apps/details?id=com.rogansoft.strengthtracker
Update:
I intend to add the 1RM calculator as a feature to this app.
UPDATE: One Rep Max Calculator has been updated to provide option for user to pay to remove all ads.