RPE stands for Rating of Perceived Exertion and is a way of measuring how difficult a set feels.
- RPE 6: approximately four repetitions remaining
- RPE 7: approximately three repetitions remaining
- RPE 8: approximately two repetitions remaining
- RPE 9: approximately one repetition remaining
- RPE 10: maximum effort with no further repetitions possible
The estimator uses RPE to account for how challenging your working sets are.