1-RM Calculator Calculator - 1-RM Estimated reps at percent of 1-repetition maximum. [Weight × ( 1 + ( 0.033 × Number of repetitions )] Baechle & Earle (2000) <thead< Reps 1 2 3 4 5 6 7 8 9 10 12 15 % of 1 RM 100 95 93 90 87 85 83 80 77 75 67 65 Weight Lifted lbs (1 kg = 2.2 lbs) Reps Completed reps (Please enter a value between 2- 10) Predicted 1-RM lbs 95% of 1-RM lbs Est. reps: 2 90% of 1-RM lbs Est. reps: 4 85% of 1-RM lbs Est. reps: 6 80% of 1-RM lbs Est. reps: 8 75% of 1-RM lbs Est. reps: 10 70% of 1-RM lbs 67% of 1-RM lbs Est. reps: 12 65% of 1-RM lbs Est. reps: 15