What is RPE in lifting?
RPE stands for rate of perceived exertion. In strength training it's a 1–10 scale of how close a set came to failure, counted in reps you had left, or reps in reserve (RIR):
- RPE 10: no reps left. Maximal effort.
- RPE 9: one more rep was possible.
- RPE 8: two reps left in the tank.
- RPE 7: three reps left; the bar still moves fast.
- RPE 6 and below: four or more reps left. Warm-up and technique territory.
Half steps such as RPE 8.5 mean "maybe one more, definitely not two". Programs written with RPE let the load follow how you feel on the day instead of a fixed number.
How does the RPE calculator work?
It uses the widely used RPE chart popularized by Reactive Training Systems, which gives the percentage of your one rep max for each combination of reps and RPE. Reps plus reps in reserve is what matters, so 5 reps at RPE 8 and 7 reps at RPE 10 both sit at 81.1% of your max.
Your estimated 1RM is the weight you lifted divided by that percentage. For example, 100 kg for 5 reps at RPE 8 is 81.1% of max, so your estimated 1RM is 123.3 kg. A triple at RPE 9 is 89.2% of that, or 110 kg. In pounds, 225 lb for 5 at RPE 8 gives an estimated 1RM of 277.4 lb.
RPE chart: % of 1RM by reps and RPE
| RPE | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 10 | 100 | 95.5 | 92.2 | 89.2 | 86.3 | 83.7 | 81.1 | 78.6 | 76.2 | 73.9 | 70.7 | 68 |
| 9.5 | 97.8 | 93.9 | 90.7 | 87.8 | 85 | 82.4 | 79.9 | 77.4 | 75.1 | 72.3 | 69.4 | 66.7 |
| 9 | 95.5 | 92.2 | 89.2 | 86.3 | 83.7 | 81.1 | 78.6 | 76.2 | 73.9 | 70.7 | 68 | 65.3 |
| 8.5 | 93.9 | 90.7 | 87.8 | 85 | 82.4 | 79.9 | 77.4 | 75.1 | 72.3 | 69.4 | 66.7 | 64 |
| 8 | 92.2 | 89.2 | 86.3 | 83.7 | 81.1 | 78.6 | 76.2 | 73.9 | 70.7 | 68 | 65.3 | 62.6 |
| 7.5 | 90.7 | 87.8 | 85 | 82.4 | 79.9 | 77.4 | 75.1 | 72.3 | 69.4 | 66.7 | 64 | 61.3 |
| 7 | 89.2 | 86.3 | 83.7 | 81.1 | 78.6 | 76.2 | 73.9 | 70.7 | 68 | 65.3 | 62.6 | 59.9 |
| 6.5 | 87.8 | 85 | 82.4 | 79.9 | 77.4 | 75.1 | 72.3 | 69.4 | 66.7 | 64 | 61.3 | 58.6 |
| 6 | 86.3 | 83.7 | 81.1 | 78.6 | 76.2 | 73.9 | 70.7 | 68 | 65.3 | 62.6 | 59.9 | 57.4 |
Questions
What's the difference between RPE and RIR?
They describe the same thing from opposite ends: RIR is reps left, and RPE is 10 minus RIR. RPE 8 is 2 RIR, RPE 9.5 is half a rep in reserve.
How accurate is RPE?
Rating effort takes practice. Lifters are usually most accurate on heavy sets close to failure and tend to underestimate how many reps they had left on lighter, longer sets. Rate each set right after you rack it, and the estimates get better over a few weeks.
What RPE should I train at?
Most strength and hypertrophy work happens between RPE 7 and 9: hard enough to drive progress, with enough left to keep technique solid and recover for the next session. Save RPE 10 for occasional tests.
How is this different from a 1RM calculator?
The 1RM calculator assumes your set went to failure. This one adjusts for the reps you had left, so it works from any set, not just all-out ones. To load the bar for your next set, use the plate calculator.