About One Rep Max
A "one rep max" (one-repetition maximum) is the maximum weight a person can lift for one complete repetition of a specific exercise while maintaining proper form. It is a measure that is commonly used in weightlifting competitions since it represents the peak force that a person's muscles can generate in an all-out effort.
A person's one rep max typically differs based on the exercise, whether it be a bench press, squat, deadlift, overhead press, or whatever other exercise is being performed. Thus, it is important to measure a one rep max for a given exercise rather than applying a one rep max in one exercise to other exercises.
How to use this calculator
After using the calculator to calculate your 1RM, there will be a save icon on the right side of the result bar. Click the save icon to save your 1RM for future reference. You can then look back at your previous 1RM for various exercises to gauge your progress.
Estimation Methods
There are various formulas used to estimate one rep max. This calculator provides calculations for the following formulas:
1RM = Weight × (1 + Reps/30)
1RM = Weight × (36 / (37 - Reps))
1RM = Weight × (Reps^0.10)