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RPE / RIR Converter

Convert between Rate of Perceived Exertion and Reps in Reserve

RPE to RIR

6 7 8 9 10
RPE

Equals

RIR

RIR to RPE

Equals

RPE

Master Formula

RIR = 10 − RPE

Pro Tip

RPE 8 means you had exactly 2 reps left in the tank. Start with clear-cut RPE values (7, 8, 9) before using half-values.

Complete RPE / RIR Reference

Full conversion table between RPE and Reps in Reserve values

RPE RIR Description
10 0 Maximum effort – Could not do another rep
9.5 0–1 Could maybe do 1 more rep
9 1 Could definitely do 1 more rep
8.5 1–2 Could do 1 to 2 more reps
8 2 Could do 2 more reps
7.5 2–3 Could do 2 to 3 more reps
7 3 Could do 3 more reps
6.5 3–4 Could do 3 to 4 more reps
6 4+ Could do 4 or more reps – Light effort

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What is RPE vs RIR?

RPE (Rate of Perceived Exertion) is an effort-based scale from 6 to 10 that measures how hard a set felt. It was adapted for strength training by powerlifter Mike Tuchscherer from the Borg scale used in sports science.

RIR (Reps in Reserve) is a capacity-based system that counts how many more reps you could have performed before reaching failure. It was popularized by researchers like Eric Helms as a more intuitive alternative to RPE.

Both systems are inverse metrics of the same concept: as effort (RPE) increases, remaining capacity (RIR) decreases. The simple formula RIR = 10 − RPE converts between them. Many modern programs use both interchangeably.

Which should I use? Some lifters find RIR more intuitive because it directly answers "how many reps did I have left?" Others prefer RPE because it is well-established in powerlifting literature. Use whichever feels more natural to rate your sets consistently.

Frequently Asked Questions

Both systems are equally valid for programming since they measure the same thing from different perspectives. RPE is more commonly used in powerlifting programs and has a longer research history, while RIR is gaining popularity in hypertrophy-focused programs. The key to accuracy with either system is consistent self-rating over time.
Half-values represent uncertainty between two whole numbers. RPE 8.5 means "I could definitely do 1 more rep, and maybe 2." In RIR terms, this translates to "1-2 reps in reserve." Half-values are useful for advanced lifters who can distinguish fine differences in effort, but beginners should stick to whole numbers initially.
Technically yes, but RPE below 6 (more than 4 reps in reserve) is not meaningfully tracked in strength training. Sets at this intensity are warm-ups or light recovery work. The RPE/RIR system is designed for productive working sets where tracking proximity to failure provides valuable training data.
The best calibration method is to occasionally take sets to RPE 10 (true failure) in a safe environment. This gives you a reference point for what maximum effort feels like. Then, work backward: if failure is RPE 10, one rep from failure is RPE 9, and so on. Video review of bar speed also helps, as bar speed decreases predictably near failure.

RPE and RIR are subjective self-rating tools. Accuracy improves significantly with training experience and consistent practice. New lifters may underestimate or overestimate effort by 1-2 points initially.