# RPE and RIR calculator

> Work out the load for any reps at a given RIR or RPE, or estimate your 1RM from a set. Full %1RM chart, the formula, its error and the research behind it.

Updated 2026-09-27. Canonical: https://povver.ai/tools/rpe-calculator

## RPE chart: % of 1RM (Epley)

| Reps | RIR 0 / RPE 10 | RIR 1 / RPE 9 | RIR 2 / RPE 8 | RIR 3 / RPE 7 |
|---|---|---|---|---|
| 1 | 100.0 | 93.8 | 90.9 | 88.2 |
| 2 | 93.8 | 90.9 | 88.2 | 85.7 |
| 3 | 90.9 | 88.2 | 85.7 | 83.3 |
| 4 | 88.2 | 85.7 | 83.3 | 81.1 |
| 5 | 85.7 | 83.3 | 81.1 | 78.9 |
| 6 | 83.3 | 81.1 | 78.9 | 76.9 |
| 7 | 81.1 | 78.9 | 76.9 | 75.0 |
| 8 | 78.9 | 76.9 | 75.0 | 73.2 |
| 9 | 76.9 | 75.0 | 73.2 | 71.4 |
| 10 | 75.0 | 73.2 | 71.4 | 69.8 |
| 11 | 73.2 | 71.4 | 69.8 | 68.2 |
| 12 | 71.4 | 69.8 | 68.2 | 66.7 |

## Epley against the RTS chart (RPE 10)

| Reps | Epley | RTS | Difference |
|---|---|---|---|
| 1 | 100.0 | 100 | 0.0 |
| 2 | 93.8 | 95 | −1.3 |
| 3 | 90.9 | 92 | −1.1 |
| 4 | 88.2 | 89 | −0.8 |
| 5 | 85.7 | 86 | −0.3 |
| 6 | 83.3 | 84 | −0.7 |
| 7 | 81.1 | 81 | +0.1 |
| 8 | 78.9 | 79 | −0.1 |
| 9 | 76.9 | 76 | +0.9 |
| 10 | 75.0 | 74 | +1.0 |

Worked example: 140 kg 1RM, 5 reps at RIR 2 → 112.5 kg (113.5 kg before rounding).

## How it works

RIR is the reps you had left when you stopped. RPE is 10 minus RIR, so RPE 8 means two reps left and RPE 10 means none (Zourdos 2016). RPE 8.5 is one or two left.

Reps plus RIR gives the reps you could have done. That goes through Epley:

- % of 1RM = 100 / (1 + (reps + RIR) / 30)
- a single with nothing left is 100%

For a load, we multiply your 1RM by that share. It rounds to the nearest 1.25 kg up to 40 kg, 2.5 kg above, or 5 lb. For your 1RM, the formula runs the other way: weight × (1 + (reps + RIR) / 30). Here RIR above 3 counts as 3, since lifters judge it poorly far from failure.

## How far to trust it

The chart is one formula. Real lifters spread around it. Pooled across studies, lifters at 80% of 1RM managed about 10 reps, give or take 2.5 from one person to the next, where Epley says 7.5. Leg exercises ran to more reps at the same load than presses (Nuzzo 2024).

Lifters misjudge RIR by about a rep, usually thinking they have fewer left than they do. They judge it better near failure and in sets of 12 or fewer (Halperin 2022).

So the 1RM comes with a likely range: reps to failure plus or minus a quarter, and one more rep when you enter RIR. Five to failure gives a narrow range. Twelve at RIR 3 gives a wide one. When the number matters, test with 1 to 6 reps near failure.

The RTS chart gives slightly different numbers. Helms and colleagues, who published an RIR-based %1RM chart, wrote that it should not be viewed as "an absolute conversion tool" (Helms 2016). The same goes for this chart.

How RPE and RIR relate, and how well lifters judge reps left, with the studies: [RPE vs RIR](/blog/rpe-vs-rir).

## In the Povver app

Povver asks for RIR on every working set and reads your last set’s RIR before it raises the weight.

## Sources

1. Zourdos MC, Klemp A, Dolan C, et al. Novel resistance training–specific rating of perceived exertion scale measuring repetitions in reserve. J Strength Cond Res. 2016;30(1):267–275. https://doi.org/10.1519/JSC.0000000000001049
2. Helms ER, Cronin JB, Storey A, Zourdos MC. Application of the repetitions in reserve-based rating of perceived exertion scale for resistance training. Strength Cond J. 2016;38(4):42–49. https://doi.org/10.1519/SSC.0000000000000218
3. Halperin I, Malleron T, Har-Nir I, et al. Accuracy in predicting repetitions to task failure in resistance exercise: a scoping review and exploratory meta-analysis. Sports Med. 2022;52:377–390. https://doi.org/10.1007/s40279-021-01559-x
4. Nuzzo JL, Pinto MD, Nosaka K, Steele J. Maximal number of repetitions at percentages of the one repetition maximum: a meta-regression and moderator analysis of sex, age, training status, and exercise. Sports Med. 2024;54(2):303–321. https://doi.org/10.1007/s40279-023-01937-7
5. Epley B. Poundage chart. Boyd Epley Workout. Lincoln, NE; 1985.
6. RPE to percentage chart (RTS-style), rpetraining.com, retrieved 27 Sep 2026. https://rpetraining.com/rpe-to-percent