RPE Calculator
Convert Rate of Perceived Exertion (RPE) and repetitions into your estimated single-rep maximum (1RM), or calculate the exact load to load on the barbell for any planned set using validated Repetitions in Reserve (RIR) percentages.
Interactive RPE & RIR load calculator
Select whether you want to estimate your 1RM from a completed set or calculate what load you should lift today based on an existing maximum. All calculations run instantly in your browser without data transmission.
How the RPE and RIR system works in strength training
The Rate of Perceived Exertion (RPE) scale used in powerlifting and barbell training is based on Repetitions in Reserve (RIR), pioneered by coach Mike Tuchscherer (Reactive Training Systems) and scientifically validated by Dr. Michael Zourdos and colleagues in 2016. [1] and [3]
Unlike traditional percentage-based training that prescribes fixed barbell loads based on a historic 1RM tested weeks or months ago, the RPE system allows for autoregulation. It accounts for daily fluctuations in neuromuscular readiness, sleep quality, psychological stress, and systemic recovery:
| RPE Rating | Repetitions in Reserve (RIR) | Subjective Sensation and Effort Level |
|---|---|---|
| 10.0 | 0 RIR | Maximal effort. Absolute zero repetitions left in the tank; form may have slowed dramatically. |
| 9.5 | 0–1 RIR | No guaranteed full rep left, but maybe could have completed one with questionable form or grind. |
| 9.0 | 1 RIR | Heavy strain. Definitely 1 clean repetition remaining before concentric failure. |
| 8.5 | 1–2 RIR | Solid working set. Definitely 1 rep left, maybe 2 reps remaining. |
| 8.0 | 2 RIR | Standard working intensity. Clean bar speed with definitely 2 repetitions left in reserve. |
| 7.5 | 2–3 RIR | Moderate-heavy load. Definitely 2 reps left, potentially 3. |
| 7.0 | 3 RIR | Brisk bar speed. Vigorous effort with 3 repetitions remaining before technical breakdown. |
| 6.5 | 3–4 RIR | Speed work or technical deload. Fast bar velocity with 3 to 4 reps in reserve. |
| 6.0 | 4+ RIR | Warmup load. High acceleration, no grinding, zero proximity to failure. |
Mathematically, every combination of repetitions and RPE corresponds to an empirical percentage of your single-rep maximum. The formula to calculate your estimated 1RM is:
Estimated 1RM = Load Lifted ÷ (%1RM from RPE Matrix ÷ 100)
Conversely, to find your target load for any prescribed set:
Target Load = Known 1RM × (%1RM from RPE Matrix ÷ 100)
Worked example: calculating 1RM and target loads from RPE
To understand how autoregulation functions during a barbell session, walk through a concrete example using a lifter performing the barbell back squat:
- Completed working set: The lifter warms up and squats 140 kg (308.6 lb) for 5 repetitions. At the end of the 5th rep, the lifter assesses that they could have completed exactly 2 more repetitions before failing. They log this set as
140 kg × 5 @ RPE 8.0. - Determine the %1RM from the RTS matrix: Cross-referencing 5 repetitions with RPE 8.0 in the Tuchscherer matrix yields 80.7% (or 0.807). [3]
- Calculate estimated 1RM (e1RM):
Estimated 1RM = 140 kg ÷ 0.807 = 173.48 kg ≈ 173.5 kg (382.5 lb)
- Prescribing the next week's heavy single: The coach's program calls for a heavy single at RPE 8.0 (1 rep @ 8 RPE = 92.2% of 1RM). Using the newly established 173.5 kg e1RM:
Prescribed Bar Weight = 173.5 kg × 0.922 = 159.97 kg ≈ 160.0 kg (352.7 lb)
If the lifter had slept poorly or suffered from acute fatigue, 140 kg might feel like an RPE 9.5 (84.9% of 1RM → e1RM drops to 164.9 kg). Autoregulation prevents overtraining by adjusting the day's training volume to actual biological capacity rather than ego.
The complete RTS RPE percentage reference matrix
The table below displays the validated percentage of 1RM for rep ranges from 1 to 10 across RPE values from 6.5 to 10.0:
| Reps | RPE 10 (0 RIR) | RPE 9.5 | RPE 9 (1 RIR) | RPE 8.5 | RPE 8 (2 RIR) | RPE 7.5 | RPE 7 (3 RIR) | RPE 6.5 |
|---|---|---|---|---|---|---|---|---|
| 1 | 100.0% | 97.8% | 95.5% | 93.9% | 92.2% | 90.7% | 89.2% | 87.8% |
| 2 | 95.5% | 93.9% | 92.2% | 90.7% | 89.2% | 87.8% | 86.3% | 84.9% |
| 3 | 92.2% | 90.7% | 89.2% | 87.8% | 86.3% | 84.9% | 83.7% | 82.1% |
| 4 | 89.2% | 87.8% | 86.3% | 84.9% | 83.7% | 82.1% | 80.7% | 79.4% |
| 5 | 86.3% | 84.9% | 83.7% | 82.1% | 80.7% | 79.4% | 78.2% | 76.8% |
| 6 | 83.7% | 82.1% | 80.7% | 79.4% | 78.2% | 76.8% | 75.3% | 73.9% |
| 7 | 80.7% | 79.4% | 78.2% | 76.8% | 75.3% | 73.9% | 72.3% | 70.7% |
| 8 | 78.2% | 76.8% | 75.3% | 73.9% | 72.3% | 70.7% | 69.4% | 67.7% |
| 9 | 75.3% | 73.9% | 72.3% | 70.7% | 69.4% | 67.7% | 66.2% | 64.7% |
| 10 | 72.3% | 70.7% | 69.4% | 67.7% | 66.2% | 64.7% | 63.3% | 61.5% |
Specialized applications: running, bench press, and training apps
RPE in running and endurance (Borg 6–20 scale vs RIR)
When runners search for an RPE calculator, they are often referencing Gunnar Borg's original 6–20 Borg Scale rather than the resistance-training 1–10 RIR scale. [4] In endurance running, Borg designed the 6–20 scale to correlate roughly with heart rate (e.g., an RPE of 13 corresponds roughly to 130 bpm in a young adult):
- RPE 6–11 (Easy / Recovery): Zone 1–2 aerobic running where you can converse in full paragraphs (the “talk test”).
- RPE 12–14 (Moderate / Tempo): Aerobic threshold where breathing is audible and sentences are broken into short phrases.
- RPE 15–17 (Hard / Threshold): Lactate threshold running; sustainable for 20 to 60 minutes with single-word communication.
- RPE 18–20 (Maximal / VO2 Max Sprints): All-out interval sprint effort sustainable for only 30 to 120 seconds.
Bench press RPE calibration
On the bench press, lifters frequently experience a steeper velocity drop-off than on the squat or deadlift. Because the bench press has a shorter total stroke and lacks the stretch-reflex rebound of a deep squat, an RPE 9.0 (1 RIR) on bench often feels like an immediate wall. Velocity tracking research by González-Badillo & Sánchez-Medina (2010) demonstrated that the terminal mean concentric velocity on a true 1RM bench press is roughly 0.15 to 0.18 m/s. If your last repetition moves faster than 0.25 m/s, you almost certainly had 1 to 2 repetitions in reserve.
Why modern powerlifting apps use RPE
In modern strength training applications, algorithmic progression replaces fixed linear percentages. By combining your daily RPE log with autoregulated formulas, the software can automatically adjust your back-off sets. For example, if your top single was scheduled at RPE 8.0 but moved at RPE 9.5, the app automatically drops subsequent working volume by 5% to 8% to protect against systemic overreaching.
Scientific limitations and psychological caveats
While RPE is a powerful tool for intermediate and advanced athletes, sports scientists have identified three notable limitations:
- Novice underestimation error: A landmark study by Hackett et al. (2017) demonstrated that untrained lifters consistently underestimate their true capacity. When asked to rate RPE, novices claimed they had 0 to 1 rep left in reserve when in reality they could complete 2 to 4 additional repetitions before failure. It takes months of technical practice and exposure to true failure to calibrate subjective exertion accurately. [5]
- High-repetition metabolic masking: Above 10 to 12 repetitions, systemic cardiovascular demand, intramuscular acidity, and local burning sensation (“the pump”) dominate perception. Lifters frequently rate a 15-rep set as RPE 9 or 10 due to pain tolerance, even when their contractile muscle fibers could technically generate more force. Reserve RPE calculations primarily for sets of 1 to 8 repetitions.
- Confirmation bias and ego: Athletes often assign an RPE that reflects what they hoped the set would feel like rather than reality. Objective tools like barbell velocity trackers (VBT) or video review of concentric bar speed provide an external check against subjective perception.
Frequently asked questions about RPE and RIR
How do I figure out my RPE?
Immediately after racking your barbell, ask yourself one question: “How many more clean repetitions could I have completed before my technique broke down or the bar pinned me?” Subtract that number from 10. If you had 2 reps left, your set was RPE 8.0. If you had 1 rep left, it was RPE 9.0. If you could not have performed another rep under any circumstances, it was RPE 10.0.
What does 7 RPE feel like?
An RPE of 7.0 corresponds to having 3 repetitions in reserve. The barbell moves briskly through the sticking point without visible deceleration. It feels challenging and requires focused bracing, but you finish the set with zero doubt that you could do three more reps.
What RPE is 90% of 1RM?
According to the RTS percentage matrix, 90% of your 1RM is roughly equivalent to a single rep at RPE 7.5 to 8.0 (90.7%–92.2%), a double at RPE 8.5 (90.7%), or a triple at RPE 9.5 (90.7%).
What percentage is 7 RPE?
The percentage depends on your repetition count. For a single rep, RPE 7.0 represents 89.2% of 1RM. For 3 reps, RPE 7.0 represents 83.7%. For 5 reps, RPE 7.0 represents 78.2%. For 8 reps, RPE 7.0 represents 69.4%.
What is the difference between RPE and RIR?
RPE (Rate of Perceived Exertion) and RIR (Repetitions in Reserve) are two sides of the same coin. RIR counts the repetitions you left in reserve (e.g., “2 RIR”), whereas RPE expresses exertion on a 1-to-10 scale where RPE = 10 - RIR (e.g., 2 RIR = RPE 8.0).
Should I train to RPE 10 every session?
No. Research consistently shows that training to absolute failure (RPE 10) on compound barbell lifts dramatically increases neuromuscular recovery time and injury risk without providing superior hypertrophic or strength stimulus over sets performed at RPE 7 to 9 (1 to 3 RIR). Keep most heavy compound work between RPE 7.0 and 8.5.
Sources
- Zourdos MC, Klemp A, Dolan C, et al. (2016). Novel Resistance Training-Specific Rating of Perceived Exertion Scale Measuring Repetitions in Reserve. Journal of Strength and Conditioning Research, 30(1), 267–275.
- Helms ER, Cronin J, Storey A, Zourdos MC (2016). Application of the Repetitions in Reserve-Based Rating of Perceived Exertion Scale for Resistance Training. Strength & Conditioning Journal, 38(4), 42–49.
- Tuchscherer M (2008). The Reactive Training Manual: Developing Autofocus for Powerlifting. Reactive Training Systems. The original RPE percentage conversion table.
- Borg GA (1982). Psychophysical bases of perceived exertion. Medicine & Science in Sports & Exercise, 14(5), 377–381.
- Hackett DA, Cobley S, Halaki M (2017). Estimation of repetitions in reserve in resistance training. Journal of Strength and Conditioning Research, 31(8), 2237–2245.
- González-Badillo JJ, Sánchez-Medina L (2010). Movement velocity as a measure of loading intensity in resistance training. International Journal of Sports Medicine, 31(5), 347–352.