Percentages work well on paper. Then your client shows up after four hours of sleep, and 80% of a max they tested two months ago feels like 90%. Or they show up fresh after a deload, and the same 80% flies. RPE is how good coaches stop fighting that. Instead of telling the client what to lift, you tell them how hard the set should feel, and the load follows.
What RPE and RIR mean in the weight room
RPE stands for rating of perceived exertion. The original Borg scale was built for cardio, but in strength training we use a 1 to 10 version anchored to reps in reserve (RIR), validated for lifting by Zourdos and colleagues in 2016:
- RPE 10: no reps left. That was everything.
- RPE 9: one more rep was there.
- RPE 8: two reps left.
- RPE 7: three reps left.
- Half points (8.5, 9.5): maybe one more, not sure.
So RPE is simply 10 minus RIR. Some clients get "2 reps left" faster than "RPE 8", and that is fine. Use whichever word lands.
The chart: turning a set into a load
The chart most powerlifting coaches use was popularized by Mike Tuchscherer of Reactive Training Systems. Each combination of reps and RPE maps to a percentage of 1RM. A few anchors:
- 1 rep at RPE 10 = 100%
- 5 reps at RPE 8 = 81.1%
- 3 reps at RPE 8 = 86.3%
- 8 reps at RPE 8 = 73.9%
That gives you two things. First, an estimated 1RM from any hard set, without testing a max: 225 lb for 5 at RPE 8 means roughly 225 / 0.811, about 277 lb. Second, a load for the next prescription: if today calls for 3 reps at RPE 8, that is about 86% of 277, so around 240 lb.
You do not need to do this math between sets. Our free RPE chart and load calculator does both steps, in pounds or kilos, and highlights the cell you are aiming for.
How to program with it, step by step
- Prescribe reps and a target RPE, not a weight. "Back squat 3x5 @ RPE 7" for a newer client, "@ RPE 8" once they read effort well.
- Use the first work set to calibrate. If 5 reps at the planned load felt like RPE 9, drop the next sets 3 to 5%. If it felt like RPE 6, add weight.
- Log the RPE of the top set. Over a few weeks, the same load at a lower RPE is progress, even when the bar weight did not move.
- Keep isolation work simple. On machines and small muscle groups, use RPE as an effort target (usually 1 to 3 reps in reserve) and skip the chart math. The percentages were built around squat, bench and deadlift.
Where RPE goes wrong
Beginners guess low. Studies on RIR ratings show that newer lifters underestimate how many reps they have left, especially when they are far from failure. A client who says "RPE 8" in month one is often at RPE 6. A simple fix: once every couple of weeks, take the last set of one exercise close to failure and compare.
High-rep sets are noisy. Past about 12 reps, the link between percentage and effort varies a lot from person to person. Treat RPE on long sets as a feel target, not a load formula.
Ego and fear both bias the number. Some clients always say 10 so they can stop. Others say 6 to look strong. Watch bar speed and form breakdown, and coach the rating like you coach technique.
RPE and autoregulation make deloads obvious
When the same load keeps creeping up in RPE across two or three sessions, fatigue is winning. That is your signal to pull volume back for a week before performance drops further. Logging RPE turns a vague "they look tired" into a trend you can show the client.
Putting it in your coaching app
In Trainer Connect you build the program with sets, reps, load and rest, and the client checks off each set on their phone or watch, in English, Spanish or Portuguese. You see every exercise's load week by week, which is exactly the history you need to read RPE trends. The free plan covers one client, so you can try the workflow before moving your roster over.
Create your free account or open the RPE calculator and plug in your client's last top set.
References: Zourdos MC et al. (2016), "Novel resistance training-specific rating of perceived exertion scale measuring repetitions in reserve", Journal of Strength and Conditioning Research 30(1). Helms ER et al. (2016), "Application of the repetitions in reserve-based rating of perceived exertion scale for resistance training", Strength and Conditioning Journal 38(4). RPE percentage chart: Reactive Training Systems (Mike Tuchscherer).