Repper is a fitness app for calculating your 1 to 15 rep max on your lifts at the gym.

You might have a workout that requires you to know your 5-rep max on the bench press, but you you only know that you can lift 275 for 1 rep. Just punch in 275 for the weight and 1 for your reps and Repper will return your 2 to 15 rep weight estimations. Repper gives you a very close approximation based on estimation methods developed by fitness specialists.