An RPE to percentage calculator converts between Rate of Perceived Exertion (RPE) on a 1–10 scale and percentage of 1RM for any number of reps. Used by powerlifters and strength coaches for autoregulation — adjusting daily training loads to match real-world readiness rather than fixed percentages that assume a constant 1RM.
Input Values
Enter to see exact target weight for this RPE and rep count
Conversion Result
Full RPE / %1RM Conversion Table
Percentage of 1RM at each RPE for 1–10 reps. Highlighted row = current selection.
| RPE | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 10 |
|---|
Borg Scale (6–20) Converter
How to Use the RPE to Percentage Calculator
Autoregulation using RPE is one of the most important advances in modern strength programming. Fixed-percentage programming assumes your 1RM is constant, but in reality daily readiness fluctuates due to accumulated fatigue, sleep, stress, and nutrition. Our RPE to percentage calculator bridges the gap between subjective effort and objective load, helping you train at the right intensity every single session.
Understanding the RPE Scale
The strength training RPE scale was popularised by powerlifting coach Mike Tuchscherer and later expanded by the Reactive Strength Institute. On this scale, RPE 10 means maximum effort — you could not complete another rep. RPE 9 means one rep left in the tank. RPE 8 means two reps in reserve, and so on. An equivalent metric is Reps in Reserve (RIR): RIR = 10 - RPE.
How to Convert RPE to % of 1RM
Select your RPE value from the dropdown, then select the number of reps performed. The calculator looks up the corresponding percentage from the RSI RPE chart, which provides percentages for each RPE × reps combination. For example, 5 reps at RPE 9 corresponds to approximately 86% of your 1RM. If you enter your 1RM, the tool also calculates the exact weight in lbs or kg to use.
Converting % of 1RM Back to RPE
Use the %1RM → RPE mode when you have a percentage-based program and want to understand the effort level it represents. Enter the programmed percentage and reps, and the calculator tells you the expected RPE. This is useful for understanding whether a percentage-based program is appropriate for your current training phase — very high RPE weeks should be followed by deload periods.
Reading the Conversion Table
The full RPE/1RM conversion table shows percentages for all RPE values from 10 down to 5 across rep ranges 1 through 10. Your current selection is highlighted in the table. Use the table as a reference when planning training blocks: if you want to train at 80% for sets of 5, the table shows this corresponds to RPE 7 (3 reps in reserve). Programmes that are too far into the RPE 9–10 zone for multiple weeks lead to overreaching.
The Borg Scale vs. RPE 1–10
The original Borg scale runs from 6 to 20 and was designed for aerobic exercise, roughly corresponding to heart rate in tens (Borg 13 ≈ 130 bpm). The 1–10 RPE scale used in strength training is a separate, modified version focused on proximity to muscular failure rather than cardiovascular effort. Use the Borg converter section when switching between aerobic and strength training contexts or when reading older exercise science literature that uses the Borg scale.
FAQ
Is this RPE calculator free to use?
Yes, this RPE to percentage calculator is completely free with no account required. All conversions run locally in your browser and no data is stored or transmitted.
Is my data safe and private?
Yes, all calculations happen entirely within your browser. Your lift data and 1RM estimates are never sent to any server or stored remotely.
What is RPE in strength training?
RPE (Rate of Perceived Exertion) in strength training is a 1–10 scale where 10 means you could not do another rep (maximum effort) and lower numbers indicate reps left in the tank. An RPE of 8 means you could have done 2 more reps. It is used for autoregulation — adjusting training loads based on daily readiness rather than fixed percentages.
What is reps in reserve (RIR)?
Reps in Reserve (RIR) is the number of additional reps you could have performed before muscular failure. RIR and RPE are inversely related: RPE 10 = 0 RIR, RPE 9 = 1 RIR, RPE 8 = 2 RIR, and so on. The Reactive Strength Institute (RSI) RPE scale popularised RIR as a practical training intensity metric.
How does RPE relate to % of 1RM?
The relationship between RPE and %1RM depends on the number of reps performed. At 1 rep, RPE 10 equals 100% 1RM. At 5 reps, RPE 10 is approximately 87–88% 1RM. The conversion table on this page uses widely cited values from strength researchers including Mike Tuchscherer and the Reactive Strength Institute.
What is the Borg scale and how is it different from RPE 1–10?
The original Borg RPE scale runs from 6 to 20 (roughly correlating to heart rate from 60 to 200 bpm). It was designed for aerobic exercise. The 1–10 RPE scale used in strength training is a modified version adapted specifically for resistance training, focusing on proximity to muscular failure rather than cardiovascular effort.
Why should I use RPE instead of fixed percentages?
Fixed percentages assume your 1RM is constant, but daily readiness fluctuates due to sleep, stress, nutrition, and accumulated fatigue. RPE-based training adjusts load to how you actually feel on a given day, which reduces overtraining risk and improves long-term consistency. Elite powerlifters and strength coaches widely advocate autoregulation using RPE.
How accurate is RPE as a training tool?
RPE accuracy improves with experience. Beginner lifters often misjudge their proximity to failure by 2–3 reps, while advanced lifters can estimate RIR within 1 rep consistently. Studies show that with 6–8 weeks of practice, even novice athletes develop reliable RPE accuracy. This calculator helps you build intuition by showing the corresponding percentage.