RPE / RIR Converter
Results
RPE
8
Reps in Reserve
2
~% of 1RM
81.1%
RPE / RIR Reference Chart
| RPE | RIR | Description |
|---|---|---|
| 10 | 0 | Maximum effort — no reps left |
| 9 | 1 | Could have done 1 more rep |
| 8 | 2 | Could have done 2 more reps |
| 7 | 3 | Could have done 3 more reps |
| 6 | 4 | Moderate effort — warm-up territory |
What Is RPE and Why Should Lifters Use It?
RPE — Rate of Perceived Exertion — is a self-reported intensity scale that tells you how hard a set was relative to your maximum effort. The modern RPE scale used in strength training runs from 6 (very light, could do many more reps) to 10 (absolute maximum, no reps left in the tank). It was adapted from Borg's original 6-20 scale and popularized in powerlifting by Mike Tuchscherer through Reactive Training Systems.
The companion concept is RIR — Reps in Reserve — which is simply how many more reps you could have performed before failure. An RPE of 8 means you had 2 reps left. An RPE of 9 means you had 1 rep left. The two scales are mirrors of each other, and many modern programs use them interchangeably.
The value of RPE is that it autoregulates your training. Percentage-based programs assume your one-rep max is static, but in reality your strength fluctuates day to day based on sleep, stress, nutrition, and accumulated fatigue. RPE lets you adjust on the fly — if 80% of your max feels like an RPE 9 today instead of the expected RPE 7, that is useful information. It means you should back off rather than grind through a prescribed weight that your body is not ready for.
How to Calibrate Your RPE Accuracy
RPE is only as useful as your ability to honestly assess it, and most lifters are terrible at it initially. The most common mistake is underestimating effort — calling a set RPE 7 when it was really an 8.5, or reporting RPE 8 on what was clearly a grinder. This is partly ego and partly inexperience. The skill improves dramatically with practice, but only if you practice honestly.
A practical approach is to periodically test: do a set at what you think is RPE 8, then attempt 2 more reps. If you genuinely get 2 more, your calibration was correct. If you only get 1, it was actually RPE 9. If you get 3, it was RPE 7. Do this for a few weeks and your internal gauge becomes much more reliable. Video review helps too — watching yourself grind through the last rep of a set you called "RPE 8" is a useful reality check.
For aging lifters and those training around injuries, RPE becomes especially valuable. After nine surgeries and 13 damaged discs, I can tell you that some days my body simply will not produce the numbers that a spreadsheet says it should. RPE gives me permission to train smart on those days instead of forcing a percentage that risks a setback. The weight on the bar matters less than the quality of the stimulus, and RPE helps you deliver the right stimulus regardless of what the calendar says.