RPE Calculator
Estimate your one rep max from a set you rated by RPE — no need to go to failure — then work out the weight for your next set at any reps and RPE.
RPE calculator
Plan your next set
What is RPE in lifting?
RPE (rating of perceived exertion) rates how hard a set was on a 1–10 scale. In strength training it is usually tied to reps in reserve: RPE 10 means you could not have done another rep, RPE 9 means one more was left, RPE 8 means two were left, and so on.
This reps-in-reserve version of the scale was described by Zourdos and colleagues in 2016. It lets you train hard without going to failure every set, and it adjusts to how strong you are on the day.
How the RPE calculator works
- Reps to failure: reps done + reps in reserve. 5 reps at RPE 8 ≈ 7 reps to failure.
- 1RM estimate: the same six published formulas as the 1RM calculator run on those reps to failure, and their average is shown with the full range.
- Next-set weight: the Epley equation solved backwards for your target reps plus reps in reserve.
Because reps to failure must stay within 12, sets that are both long and easy (for example 10 reps at RPE 7) are not estimated — they are too far from a max to predict reliably.
RPE chart: % of 1RM by reps and RPE
Each cell is the percentage of your 1RM for that many reps at that RPE, calculated with the Epley equation on reps to failure. Real lifters vary, so use it as a starting point.
| Reps | RPE 10 | RPE 9 | RPE 8 | RPE 7 | RPE 6 |
|---|---|---|---|---|---|
| 1 | 100.0% | 93.8% | 90.9% | 88.2% | 85.7% |
| 2 | 93.8% | 90.9% | 88.2% | 85.7% | 83.3% |
| 3 | 90.9% | 88.2% | 85.7% | 83.3% | 81.1% |
| 4 | 88.2% | 85.7% | 83.3% | 81.1% | 78.9% |
| 5 | 85.7% | 83.3% | 81.1% | 78.9% | 76.9% |
| 6 | 83.3% | 81.1% | 78.9% | 76.9% | 75.0% |
| 7 | 81.1% | 78.9% | 76.9% | 75.0% | 73.2% |
| 8 | 78.9% | 76.9% | 75.0% | 73.2% | 71.4% |
| 9 | 76.9% | 75.0% | 73.2% | 71.4% | — |
| 10 | 75.0% | 73.2% | 71.4% | — | — |
— means more than 12 reps to failure, where estimates are not shown.
How accurate is RPE?
RPE depends on your own judgement. A review of the research by Stronger by Science reports that, on average, lifters misjudge their reps in reserve by about one rep — enough to move a 1RM estimate by a few percent. If you are new to RPE, check your ratings occasionally by taking a set to a safe failure (for example on a machine or with safeties set), and use thestandard 1RM calculator for sets taken close to failure.
Related tools and guides
- One Rep Max Calculator
Estimate a 1RM for any lift with all six formulas side by side.
- 1RM Percentage Calculator
Turn a known 1RM into working weights, e.g. 80% for sets of five.
- 1RM Formula Guide
All six equations compared rep by rep, and which to trust when.
- Warm-up Calculator
Build a warm-up ramp to your top set, with loadable weights.
Sources
- Zourdos, M. C., 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. Link (opens in a new tab)
- Stronger by Science. Reps in reserve (RIR): research review and practical guide. Link (opens in a new tab)
- Epley, B. (1985). Poundage Chart. Boyd Epley Workout. Lincoln, NE: Body Enterprises. (A coaching chart, not a peer-reviewed study.)