Definition
RPE is a self rating of effort on a 1–10 scale, where 10 is a true max and the number of reps below 10 equals reps left in reserve (RIR). An RPE 8 means you could have done 2 more reps. It lets you scale daily loads to how you actually feel, instead of forcing a percentage on a bad day.
Real questions
What's the difference between RPE and RIR?
RIR (reps in reserve) is just RPE inverted: RPE 9 = 1 RIR, RPE 8 = 2 RIR, and so on.
Is RPE accurate for beginners?
Less so — new lifters often underestimate effort. Spend 6–12 months training before relying heavily on RPE to autoregulate.
Stack with
Put it to work
Coach Foster builds your program around rpe (rate of perceived exertion) and the rest of the fundamentals, shaped to your body and your week.