How the RPE chart works
The chart links three things: reps, RPE and the percentage of your one-rep max (1RM). If you know any two, you can find the third. Enter a recent hard set and the calculator estimates your 1RM; choose a target reps and RPE and it gives you the weight to use.
Estimated 1RM = weight lifted ÷ chart %
Target weight = 1RM × chart % for the target reps and RPE
Percentages come from Mike Tuchscherer's Reactive Training Systems (RTS) RPE chart, the most widely used version in powerlifting.
RPE and RIR explained
| RPE | Reps in reserve | What it feels like |
|---|---|---|
| 10 | 0 | Maximum effort; no more reps possible |
| 9.5 | 0–1 | Couldn't do another rep, maybe more weight |
| 9 | 1 | One more rep possible |
| 8.5 | 1–2 | Definitely one more, maybe two |
| 8 | 2 | Two more reps possible |
| 7 | 3 | Fast, heavy-ish; three more reps |
| 6.5 and below | 4+ | Warm-up or speed work |
Using RPE in your training
- Most strength work lives at RPE 7–9; keep true RPE 10 sets rare.
- Use the estimated 1RM from your top set to set back-off sets for the rest of the session.
- On bad days RPE automatically lowers the load; on good days it lets you push.
Frequently asked questions
What does RPE mean in lifting?
RPE (rating of perceived exertion) rates how hard a set was by how many more reps you could have done. RPE 10 means no reps left, RPE 9 one rep left, RPE 8 two reps left, and half points mean you might have managed one more.
What is the difference between RPE and RIR?
They describe the same thing from opposite ends: reps in reserve (RIR) = 10 − RPE. An RPE 8 set is a 2 RIR set.
How accurate is an RPE-based 1RM estimate?
Estimates are most reliable from sets of 1–5 reps at RPE 8 or higher, and less reliable above about 8 reps. Rating RPE takes practice, so beginners often underestimate how many reps they had left.
General fitness information, not medical advice. Results are estimates; check with a doctor or qualified coach before major changes to diet or training. Last reviewed 2026-09-27.