RPE vs RIR: A Simple Guide to Lifting Effort

RIR means repetitions in reserve: how many more repetitions you think you could have completed with the same acceptable technique. RPE means rating of perceived exertion: a score describing how demanding an effort felt. In lifting, an RIR-based RPE scale connects the two, but not every RPE scale uses those anchors. Always make clear which system your program means.

Use the lifting-specific scale

The table shows common approximate anchors for the RIR-based scale described in resistance-training research. It is a communication tool, not an exact conversion of your feelings into a laboratory measurement. Other whole-session or aerobic RPE scales should not automatically be read as repetitions left.

Apply it to one actual set

Imagine you finish ten repetitions of a row and estimate you could still perform two more without shortening the movement or changing technique. Record ten repetitions at approximately 2 RIR, or RPE 8 on this scale. This describes the set you completed. It does not mean you must perform those extra repetitions to confirm the score.

Use a clear stopping standard. If an extra repetition would require bouncing, a large change in body position or losing the intended range, it may not meet your acceptable-technique definition. Different exercise variations have different limits, so keep the standard consistent when comparing sessions.

Expect estimates to be imperfect

Beginners may find it difficult to judge how much remains, and even experienced lifters can misjudge a set. Sleep, unfamiliar movements and higher repetition sets can complicate perception. Write approximate rather than pretending every score is exact. Look for useful patterns across multiple visits.

A program might use a couple of repetitions in reserve to keep effort manageable while learning, but that is an example target, not a universal optimum. ACSM's 2026 guidance does not require every healthy adult to train to failure. The aim is to match effort to the task while maintaining controlled, repeatable work.

Is RPE 8 the same as 80% of maximum weight?

No. RPE describes perceived effort; percentage of one-repetition maximum describes relative load. The same load can feel different with different repetitions, fatigue or exercise setup.

What if I am unsure?

Start with a short description such as a few good repetitions left and improve your consistency with practice. You do not need to test failure on every set.

Pair this with the working-weight guide and workout logging example.

Sources

• Zourdos et al., 2016
• ACSM 2026

If keeping a record would help you follow this plan, you can try logging your workouts in GYMDONE and review what you did before your next session.