FormaGet FormaRIR vs RPE: two views of set effort.
RIR counts estimated repetitions remaining. The resistance-training RPE scale expresses the same proximity-to-failure idea as a rating near the top of a 1 to 10 scale.
Published and last reviewed September 14, 2026 · 7-minute read
RIR to RPE conversion chart
| RIR | RPE | Meaning |
|---|---|---|
| 0 RIR | RPE 10 | No additional complete repetition was available. |
| 1 RIR | RPE 9 | You estimate one repetition remained. |
| 2 RIR | RPE 8 | You estimate two repetitions remained. |
| 3 RIR | RPE 7 | You estimate three repetitions remained. |
| 4 RIR | RPE 6 | You estimate four repetitions remained. |
This simplified chart covers the scale's common whole-number range near failure. The published scale also uses descriptive anchors and half steps.
What each number communicates
RIR is the concrete estimate
“2 RIR” says the lifter believes two more complete repetitions were possible with the intended technique.
RPE is the effort rating
“RPE 8” places that estimate on the resistance-training-specific effort scale. It is not the same as saying the load was 80% of 1RM.
A lifting example
You complete eight bench-press repetitions and estimate that two more were available. You can record either 2 RIR or RPE 8. Both describe perceived proximity to failure for that set. Neither number proves the exact repetition capacity or automatically determines the next load.
Keep the scale specific
“RPE” is also used in endurance and clinical settings with other anchors. This page refers to the resistance-training RIR-based scale, not every perceived-exertion scale.
Accuracy and useful limits
A scoping review and exploratory meta-analysis covering 12 studies found that people underpredicted repetitions to task failure by 0.95 repetitions on average, with considerable individual variation. Accuracy tended to improve closer to failure, with heavier loads, and during lower-repetition sets.
Use RIR or RPE as repeatable context beside exercise, load, repetitions, range, and technique. Do not present a subjective rating as a direct physiological measurement.
Frequently asked questions
What is the difference between RIR and RPE?
RIR states how many additional repetitions you believe remained before task failure. Resistance-training RPE rates the completed set's effort on a 1 to 10 scale anchored to that estimated reserve near failure.
How do you convert RIR to RPE?
On the common whole-number portion of the resistance-training scale, subtract RIR from 10. Zero RIR corresponds to RPE 10, 1 RIR to RPE 9, 2 RIR to RPE 8, and 3 RIR to RPE 7.
Is RPE 8 always 2 RIR?
RPE 8 is anchored to about 2 RIR on the resistance-training RIR-based scale. The rating remains a subjective estimate, so it does not prove that exactly two repetitions were available.
Is RPE the same as percentage of 1RM?
No. RPE describes perceived effort, while percentage of 1RM describes load relative to a tested or estimated maximum. The same RPE can occur at different percentages depending on repetitions, exercise, and the lifter.
Sources
Journal of Strength and Conditioning Research, 2016. PMID: 26049792.
Strength and Conditioning Journal, 2016. PMID: 27531969.
Scoping review and exploratory meta-analysis, 2022. PMID: 34542869.
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