Rate of Perceived Exertion (RPE)
Rate of perceived exertion (RPE) is a subjective scale — most commonly 0–10 in strength training — that rates how hard a set or session felt. In lifting, RPE is often anchored to reps in reserve (RIR): an RPE of 8 means roughly two good reps were left in the tank.
Why it matters
RPE lets you autoregulate effort without needing to know your exact maxes every day. It also feeds the most widely used training-load metric, session RPE (sRPE = RPE × duration), which underpins ACWR and load monitoring. For everyday athletes, RPE is a simple, free way to make 'how hard was that?' a usable number.
How it's measured
RPE is self-reported immediately after a set or session. In resistance training the RPE–RIR map is roughly: RPE 10 = no reps left, RPE 9 = 1 rep left, RPE 8 = 2 reps left, and so on. For whole sessions, session RPE multiplied by duration in minutes gives a single training-load value used in workload tracking.
ACWR Calculator — turn session RPE into a workload ratio
Frequently asked questions
What is the difference between RPE and RIR?
They describe the same thing from opposite ends. RIR (reps in reserve) counts how many reps you could still have done; RPE rates how hard it felt. RPE 8 corresponds to about 2 RIR, RPE 9 to about 1 RIR, and RPE 10 to 0 RIR.
How is session RPE used to measure training load?
Session RPE (sRPE) multiplies your whole-session RPE (0–10) by its duration in minutes. A 60-minute session at RPE 7 equals a load of 420. Summing these values across days drives load-monitoring tools such as the acute:chronic workload ratio.
Educational, performance-oriented content for athletes — not medical advice. Thresholds and reference ranges come from group data and vary between individuals.