Workout guides Effort & strength
What Is RPE in Strength Training?
RPE means Rating of Perceived Exertion: how hard an effort feels. In a reps-in-reserve lifting scale, RPE 8 means you estimate that about two additional repetitions were possible at the end of the set with the intended technique.
By Aika · Reviewed
What RPE means in lifting
RPE is a subjective rating of effort. This guide uses the repetitions-in-reserve scale for resistance training: you estimate how many further repetitions were available when the set ended. RIR names that reserve directly.
Rate the set you actually performed: its exercise, range of motion, tempo and number of reps. Two sets with the same weight can receive different ratings if one has more repetitions or comes later in the session.
The RPE and RIR chart
| RPE | Estimated repetitions left | How to read it |
|---|---|---|
| 6 | About 4 | Several more reps available |
| 7 | About 3 | Three more reps estimated |
| 8 | About 2 | Two more reps estimated |
| 9 | About 1 | One more rep estimated |
| 10 | 0 | No additional rep available under the intended technique |
These are estimates, not measurements of a hidden rep counter. RPE 10 is not the same as 1RM. A set of eight can reach 0 RIR even though its weight is below a one-rep maximum. Conversely, a single repetition with a light load can leave many more reps available.
The table is most useful when the program explicitly uses this lifting scale. It should not be applied to every scale that happens to use the letters RPE.
How to read 3×10 @ RPE 8
Example: three sets of ten
Perform ten repetitions in a set. The target is to finish feeling that approximately two more reps were available with the same intended technique. Rest as prescribed, then perform the next set.
The ten prescribed reps remain the task. “Two in reserve” does not mean adding two bonus repetitions to demonstrate that they were possible. The effort target helps describe where the set should end.
If the first set felt like RPE 8 but the last like RPE 9, record that difference. Whether to adjust the load for a later set depends on the program’s instructions; RPE notation alone does not specify an exact kilogram change.
RPE vs percentage of 1RM
Percentage-based training specifies load relative to a reference. With a 100 kg reference maximum, 70% gives 70 kg. RPE describes the perceived difficulty of the set, which also depends on reps, tempo, rest and the athlete.
For example, five reps and ten reps at that same 70 kg are different tasks. Knowing the percentage alone does not tell you that both will be RPE 8. A program can combine a percentage with an RPE target, but those are two pieces of information rather than interchangeable labels.
Why your estimate can change between sets
A short rest, more accumulated fatigue, or a change in movement execution can alter how the next set feels. Consistent notes make the rating more useful: record load, reps, rest, any prescribed tempo, and the RPE you observed.
Compare like with like. A paused squat and a faster unpaused squat are not identical sets even if the bar weighs the same. The tempo guide explains how to identify that difference in the prescription.
Use Aika for the assigned recovery period between sets. Consistent timing makes it easier to know whether the rest interval changed when you review your session.
Lifting RPE vs cardio RPE
A running session might also use an effort rating, but it is not asking how many additional lifting reps remain. Borg’s 6–20 scale, other numerical effort scales and whole-session ratings have their own context.
Do not convert a lifting RPE 8 into 80% of maximum heart rate, Zone 4, or a fixed running pace. Check which scale the program names. For intensity ranges expressed through heart rate, read heart rate zones explained; for sets and symbols, read workout notation.
Common questions
What does RPE 8 mean?
On the reps-in-reserve lifting scale used here, approximately two more repetitions were possible when the set ended. It describes your estimate at the end of that particular set.
Is RPE 10 always a one-rep max?
No. RPE 10 means no further repetitions were available under the intended technique. That can happen at the end of a set of one, five, ten or another number of reps.
Is 2 RIR the same as RPE 8?
Approximately, on this RIR-based strength-training scale. It is an estimate, and the relationship is not a conversion rule for every effort scale.
Can I convert RPE directly to heart rate?
No. A lifting set’s RPE and a heart rate zone measure different things. You cannot read “RPE 8” as a specific heart rate or percentage of maximum heart rate.