RPE vs RIR: How to Rate Your Sets (and Why It Helps You Progress)
RPE and RIR both describe how hard a set was by counting the reps you had left. Here's how each scale works, how to convert between them, and how to use them to pick your weights.
By Rayyan Siddique, founder of RepEight
Two lifters both do 100 kg for 5 on squat. For one it was a warm-up. For the other it was nearly a max. The weight and reps don't tell you how hard the set was, and how hard it was is what drives progress.
That's what RPE and RIR are for.
RIR: reps in reserve
RIR is the simplest version. After a set, ask: how many more good reps could I have done?
- 0 RIR: nothing left, true failure
- 1 RIR: one more rep
- 2 RIR: two more
- 3+ RIR: comfortable
RPE: rating of perceived exertion
RPE rates the same thing on a 1–10 scale. In lifting, the widely used version, set out by Zourdos and colleagues in 2016, ties the numbers directly to reps in reserve:
| RPE | Meaning | RIR |
|---|---|---|
| 10 | Max effort, no reps left | 0 |
| 9.5 | Maybe could add a little weight, no more reps | 0–1 |
| 9 | One rep left | 1 |
| 8.5 | One, maybe two left | 1–2 |
| 8 | Two reps left | 2 |
| 7 | Three reps left | 3 |
| 6 and below | Warm-up territory | 4+ |
So they're two ways of saying the same thing: RPE = 10 − RIR.
Why rate your sets at all?
It auto-adjusts to your day
A program that says "3 × 5 at RPE 8" means a lighter bar on a bad night's sleep and a heavier one when you're flying. Fixed percentages can't do that.
It makes volume count
The research on sets per week is about hard sets. Rating your sets tells you which ones actually count.
It shows progress that the bar doesn't
Doing 100 kg × 5 at RPE 7 when it was RPE 9 a month ago is progress, even though the numbers on the bar haven't changed.
How to use RPE to choose a weight
- Do your first working set and rate it honestly.
- If it was easier than the target RPE, add weight. If it was harder, drop some.
- Keep the rest of your sets around the target.
To turn a set into an estimated one-rep max, or to work out what to load for a different rep range, use the free RPE calculator. It uses the standard RPE chart to convert between reps, RPE and percentage of 1RM.
Getting better at rating
- Be honest, not tough. Most people call a set RPE 8 when it was really a 6.
- Film a set now and then. If the bar speed barely slowed, you had more in the tank.
- Occasionally go to failure on a safe exercise, like a machine or dumbbell curl, to calibrate what 0 RIR feels like.
Log your RPE alongside each set in RepEight and your coach can see how hard sessions really were, not just what was on the bar.
FAQ
What does RPE 8 mean in lifting?
RPE 8 means you could have done about two more reps with good form. It's a common target for main strength work.
How do you convert RPE to RIR?
RIR = 10 − RPE. So RPE 9 is 1 RIR, RPE 8 is 2 RIR and RPE 7 is 3 RIR.
Is RPE accurate for beginners?
Beginners tend to underestimate how many reps they have left, especially on higher-rep sets. Accuracy improves with practice, usually within a few weeks.
Put it into practice
Train with a coach that remembers you
RepEight logs every set, tracks your PRs automatically and has an AI coach that plans around your real numbers.