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.
Sources
The formula on this page comes from the published work below. We check the numbers against the worked examples in these sources with automated tests, and re-read the page against them when we review it.
- Zourdos MC, Klemp A, Dolan C, et al. Novel resistance training-specific rating of perceived exertion scale measuring repetitions in reserve. J Strength Cond Res. 2016;30(1):267–275. pubmed.ncbi.nlm.nih.gov/26049792/
- Helms ER, Cronin J, Storey A, Zourdos MC. Application of the repetitions in reserve-based rating of perceived exertion scale for resistance training. Strength Cond J. 2016;38(4):42–49. pubmed.ncbi.nlm.nih.gov/27531969/
- Tuchscherer M. Reactive Training Systems — RPE chart relating reps, repetitions in reserve and percentage of one-rep max. www.reactivetrainingsystems.com/
General fitness information, not medical advice. Results are estimates; check with a doctor or qualified coach before major changes to diet or training. Formula and copy last reviewed 27 September 2026.