Free Tool · Strength Training
RPE Calculator
Two tools in one. Estimate your 1RM from any working set, or find the exact weight to load for a given rep and RPE target. Includes the full RPE chart with every percentage.
| Reps | RPE 10 | RPE 9.5 | RPE 9 | RPE 8.5 | RPE 8 | RPE 7.5 | RPE 7 | 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% | 86.4% | 85.0% |
| 3 | 92.2% | 90.7% | 89.2% | 87.8% | 86.4% | 85.0% | 83.7% | 82.4% |
| 4 | 89.2% | 87.8% | 86.4% | 85.0% | 83.7% | 82.4% | 81.1% | 79.8% |
| 5 | 86.3% | 85.0% | 83.7% | 82.4% | 81.1% | 79.9% | 78.6% | 77.4% |
| 6 | 83.7% | 82.4% | 81.1% | 79.9% | 78.6% | 77.4% | 76.2% | 75.1% |
| 7 | 81.1% | 79.9% | 78.6% | 77.4% | 76.2% | 75.1% | 73.9% | 72.3% |
| 8 | 78.6% | 77.4% | 76.2% | 75.1% | 73.9% | 72.3% | 70.7% | 69.4% |
| 9 | 76.2% | 75.1% | 73.9% | 72.3% | 70.7% | 69.4% | 68.0% | 66.7% |
| 10 | 73.9% | 72.3% | 70.7% | 69.4% | 68.0% | 66.7% | 65.3% | 64.0% |
| 11 | 70.7% | 69.4% | 68.0% | 66.7% | 65.3% | 64.0% | 62.6% | 61.3% |
| 12 | 68.0% | 66.7% | 65.3% | 64.0% | 62.6% | 61.3% | 59.9% | 58.6% |
How to use RPE
Effort, measured in reps
RPE replaces fixed percentages with a self-reported effort score. Instead of always pressing 70 percent of your 1RM on squat day, you chase a target RPE. If you are underslept or stressed, the weight self-adjusts down. If you are fresh, it goes up. Mike Tuchscherer popularized the 10-point scale in powerlifting, and it is now the default in evidence-based hypertrophy programming.
The simplest way to learn RPE is to start from RIR. Count reps in reserve: if you have 2 reps left, that is RIR 2, which equals RPE 8. Most lifters can call RIR accurately within 2 reps of failure after a few weeks of deliberate practice.
Conversion cheat sheet
RIR to RPE, at a glance
Frequently asked questions
Questions we hear a lot
RPE stands for Rate of Perceived Exertion. On the 10-point Mike Tuchscherer scale used in strength training, RPE 10 means you could not have done another rep, RPE 9 means one rep left in reserve, RPE 8 means two reps left, and so on down to RPE 6.5. It captures how hard a set actually felt.
RIR stands for Reps in Reserve, the number of additional reps you could have done. The two are directly linked: RPE = 10 minus RIR. So a set with 2 reps in reserve is RPE 8. Lifters often prefer RIR because it is easier to judge how many reps were left than to estimate an effort rating.
When logged honestly within 2 to 3 reps of failure, the RPE chart produces estimates within about 5 percent of a measured 1RM for trained lifters. Accuracy drops for sets taken well short of failure or for very high rep sets, because perceived effort flattens out in those ranges.
Yes. Most evidence-based programs prescribe an RPE range per set rather than a fixed weight, which lets the weight adjust to how you feel on the day. Typical ranges: RPE 7 to 8 for most hypertrophy work, RPE 8 to 9 for heavier strength sets, RPE 9 to 10 only on the final rep-out or test.
RPE 7 to 9 captures the sweet spot for muscle growth. Dropping below RPE 6 wastes volume on sets too far from failure to generate meaningful adaptation; training consistently at RPE 10 accumulates fatigue faster than it drives growth.
Yes. The Sculpt AI RPE calculator is free and requires no account. The Sculpt AI app applies these same methods automatically to every set you log, so you never need to reach for a calculator mid-workout.
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