The three formulas below describe how the One Rep Max Calculator arrives at your 1RM estimates.
One Rep Max Calculator Method 1:
1RM = ((Number of Reps / 30) + 1) x Weight Used
One Rep Max Calculator Method 2:
1RM = Weight Used / (1.0278 - (0.0278 x Number of Reps))
One Rep Max Calculator Method 3:
1RM = (Weight Used) x 36 / (37 - Number of Reps)