RPE calculator
Rate of perceived exertion turns how hard a set felt into numbers. Enter a set you did, and this estimates your max from it and works out the load for the set you plan next.
RPE Calculator
RPE (rate of perceived exertion) rates a set from 6 to 10 by how many reps were left in the tank: RPE 10 is failure, RPE 9 leaves one rep in reserve, RPE 8 leaves two. On the RTS chart a set of 5 at RPE 8 is about 81 percent of one-rep max, so 100 kg for 5 at RPE 8 implies a max near 123 kg and a single at RPE 8 of about 113 kg.
That set was 81.1% of max, 2 reps in reserve
Loads at RPE 8
Method notes (2)
- RTS-style RPE chart: the load depends on how many reps the set is from failure (reps + reps in reserve).
- RPE is a self-rating, so the estimate is only as honest as the rating. It is least reliable for beginners and above 10 reps.
Metric or imperial · runs the same code as the app · nothing is sent anywhere
How it works
Reps in reserve is RIR = 10 − RPE. The percentage of 1RM depends only on how far the set was from failure, reps + RIR, read off the RTS chart: 100% for a single at RPE 10, 92.2% for a single at RPE 8 or a triple at RPE 10, 81.1% for 5 at RPE 8, and so on down to 68% for 12 at RPE 10.
The estimated max is weight / %, and the next set's load is that max times the chart percentage for its reps and RPE, rounded to the nearest 0.5. Half-point RPEs sit halfway between the whole ones.
Common questions
What RPE should I train at?
Most working sets for strength and size land at RPE 7 to 9, one to three reps short of failure. That is close enough to failure to drive progress while leaving enough in reserve to recover between sessions.
Is RPE better than percentages?
It adapts to the day. A fixed percentage ignores sleep, stress and fatigue; RPE lets the load move with how strong you are that session. Many programmes combine them: a percentage to start from, RPE to adjust.
How do I get better at rating RPE?
Film sets and compare, and test your ratings now and then by taking a set to true failure safely. Beginners tend to underrate how many reps they have left, so ratings get more accurate with experience.
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