The Tiger Fitness one rep max calculator performs 2 functions:
You can plug in any weight and number of reps, and calculate your approximate one rep max for that exercise.
You can obtain workout percentages that are based upon a one rep max, even if you never test your max.
The information that this one rep max calculator provides can be extremely useful to lifters who rarely/never test their max. A number of popular muscle and strength building workout routines reference percentages of your one rep max. This calculator will provide you with solid estimates based on any weight and rep scheme from a recent workout.