This app calculates the one-rep max of a given exercise using the amount of weight lifted and the number of reps the user is able to do with that given weight. This app using the following formulas to calculate one-rep maxes:

Bryzycki formula: $weight\ast (36\mathrm{/}(37-numberofreps))weight\; *\; (36/\; (37\; -\; number\; of\; reps))$

Epley formula: $weight\ast (1+(0.0333\ast numberofreps))weight\; *\; (1\; +\; (0.0333\; *\; number\; of\; reps))$

Lombardi formula: weight * (number of reps ^ 0.1)

O'Conner formula: $weight\ast (1+(0.025\ast numberofreps))weight\; *\; (1\; +\; (0.025\; *\; number\; of\; reps))$