Strength
RPE vs RIR: how to use the RPE scale in strength training
Percentages of your one-rep max work well on paper, but you are not equally strong every day. Sleep, stress and fatigue all shift what a “70%” set feels like. RPE — rating of perceived exertion — lets you adjust the weight to how you actually perform on the day.
RPE and RIR: the same idea, two names
The original RPE scale, created by Gunnar Borg, runs from 6 to 20 and was designed for endurance exercise. Strength coaches adapted it into a 1–10 scale based on reps in reserve (RIR): how many more reps you could have done before failure. Powerlifting coach Mike Tuchscherer popularised it, and Zourdos and colleagues described a formal version in 2016.
| RPE | Reps in reserve | What it feels like |
|---|---|---|
| 10 | 0 | Maximal — no more reps, no more weight |
| 9.5 | 0 | No more reps, but maybe slightly more weight |
| 9 | 1 | One more rep was possible |
| 8.5 | 1–2 | Definitely one more, maybe two |
| 8 | 2 | Two more reps were possible |
| 7 | 3 | Three more reps; bar speed still quick |
| 6 and below | 4+ | Warm-up or technique work |
So RPE 8 and “2 RIR” describe the same set. Use whichever wording your program uses.
How to rate a set honestly
- Rate it straight after the last rep, before you rack the bar and walk away.
- Ask “how many more clean reps could I have done?”, not “how hard did it feel?”.
- Watch bar speed: a sharp slowdown on the last rep usually means RPE 9 or higher.
- Expect to be off at first. Ratings tend to be more accurate close to failure and get better with practice, so beginners often under-rate sets.
Turning RPE into weights
An RPE chart links reps and RPE to a percentage of your one-rep max. A few rows from the Reactive Training Systems chart:
| Reps | RPE 10 | RPE 9 | RPE 8 | RPE 7 |
|---|---|---|---|---|
| 1 | 100% | 95.5% | 92.2% | 89.2% |
| 3 | 92.2% | 89.2% | 86.3% | 83.7% |
| 5 | 86.3% | 83.7% | 81.1% | 78.6% |
That lets you do two things:
- Estimate your 1RM from a hard set. 140 kg for 3 reps at RPE 8 is 86.3% of your max, so your estimated 1RM is 140 ÷ 0.863 ≈ 162 kg.
- Pick the weight for your next set. If the program says 5 reps at RPE 8, that’s 81.1% of 162 kg ≈ 131.5 kg.
When to use RPE
RPE works best for experienced lifters who can judge their sets and want training to flex with their recovery. Beginners usually do better with simple progression — add a little weight each session — while they learn what a hard set feels like. A common middle ground is a fixed top set at RPE 8, then back-off sets at a set percentage of that weight.
The chart is an average. If your estimated max is consistently higher or lower than what you actually lift, you are probably a little more or less “reps-tolerant” than average — adjust your targets rather than the chart.
Try the RPE Calculator & ChartEstimate your 1RM from any hard set, then pick weights by reps and RPE.General fitness information, not medical advice. Check with a doctor or qualified coach before major changes to diet, supplements or training.