One Rep Max Calculator calculates your one rep maximum and stores your one rep maximum records.
Features:

Lifts:
Enter the lifts you use with the Lift Name Editor.

Calculator:
7 selectable methods calculated: Brzycki, Epley, Lander, Lombardi, Mayhew, Oconner, and Watham.
Scales your one rep maximum between 50% and 100%.
Displays average for each formula and scaled value.

Record Keeping:
For each lift, you can store the date, reps, weight, and one rep max.
Your one rep max records can be exported to external storage.

Graph
A plot of your one rep max values is displayed.

This is the best one rep max calculator because it displays seven calculation methods, percent max, and average all in one user friendly table.