RPE Calculator

Enter a set you did (weight, reps and RPE) to estimate your one-rep max, then pick a target set to get its load. The numbers come from the Reactive Training Systems RPE chart, printed in full below.

Estimated 1RM 277.4 lb

225 lb × 5 reps at RPE 8 is 81.1% of 1RM on the RTS chart: 225 ÷ 0.811 = 277.4 lb.

3 reps at RPE 9 245 lb

89.2% of 277.4 lb = 247.5 lb, rounded to the nearest 5 lb.

RPE chart: percent of 1RM by reps and RPE

Find your reps along the top and your RPE down the side. Each cell is the share of your one-rep max that the set took: 5 reps at RPE 8 is 81.1%. The chart covers 1–12 reps and RPE 6.5–10 in half steps, the range Reactive Training Systems publishes; it has no RPE 6 row.

Percent of 1RM by reps (columns) and RPE (rows), Reactive Training Systems chart
RPE / reps	1	2	3	4	5	6	7	8	9	10	11	12
10	100.0%	95.5%	92.2%	89.2%	86.3%	83.7%	81.1%	78.6%	76.2%	73.9%	70.7%	68.0%
9.5	97.8%	93.9%	90.7%	87.8%	85.0%	82.4%	79.9%	77.4%	75.1%	72.3%	69.4%	66.7%
9	95.5%	92.2%	89.2%	86.3%	83.7%	81.1%	78.6%	76.2%	73.9%	70.7%	68.0%	65.3%
8.5	93.9%	90.7%	87.8%	85.0%	82.4%	79.9%	77.4%	75.1%	72.3%	69.4%	66.7%	64.0%
8	92.2%	89.2%	86.3%	83.7%	81.1%	78.6%	76.2%	73.9%	70.7%	68.0%	65.3%	62.6%
7.5	90.7%	87.8%	85.0%	82.4%	79.9%	77.4%	75.1%	72.3%	69.4%	66.7%	64.0%	61.3%
7	89.2%	86.3%	83.7%	81.1%	78.6%	76.2%	73.9%	70.7%	68.0%	65.3%	62.6%	59.9%
6.5	87.8%	85.0%	82.4%	79.9%	77.4%	75.1%	72.3%	69.4%	66.7%	64.0%	61.3%	58.6%

The chart is one series shifted by a rep per RPE point. For example, 4 reps at RPE 8, 5 reps at RPE 9 and 6 reps at RPE 10 are all 83.7%, because each is a set you could have stretched to 6 reps.

Some RPE charts online use slightly different numbers; one lists a single at RPE 9.5 as 98.0%. The values here are the ones Reactive Training Systems publishes, where that cell is 97.8%. Mike Tuchscherer of Reactive Training Systems adds: “it is best if you customize the given RPE chart to fit yourself as an athlete.”

Estimating 1RM and target loads from RPE

The calculator finds your set on the chart and divides. 225 lb for 5 reps at RPE 8 is 81.1%, so your estimated 1RM (e1RM) is 225 ÷ 0.811 = 277.4 lb.

For the target set it multiplies back. 3 reps at RPE 9 is 89.2%, and 89.2% of 277.4 lb is 247.5 lb. Loads are rounded to the nearest 5 lb (2.5 kg) by default, so the calculator shows 245 lb; you can also round to 2.5 lb, 1 lb or not at all.

If you already know your 1RM, enter it as 1 rep at RPE 10. That cell is 100%, so the e1RM is the weight itself and target loads come straight from it.

Helms and colleagues note that loads taken from a percent of an old 1RM test don't account for day-to-day changes in strength. Rating each set and working from it lets the next load follow how you perform on the day.

RPE as reps in reserve (RIR)

In lifting, RPE is scored by the reps you had left at the end of the set. This is the scale Zourdos and colleagues published in 2016:

RIR-based RPE scale (Zourdos et al. 2016, reprinted in Helms et al. 2016)
RPE	Meaning
10	Maximum effort
9	1 rep remaining
8	2 reps remaining
7	3 reps remaining
5–6	4–6 reps remaining
3–4	Light effort
1–2	Little to no effort

The RTS chart adds half steps such as 8.5, between two reps left and one. Helms and colleagues point out that a scale of this kind first appeared in The Reactive Training Systems Manual in 2008, from the company that publishes the chart above. In the 2016 study, experienced squatters rated their 1RM attempts closer to 10 than novices did (9.80 against 8.96), and Helms and colleagues advise new lifters to practice rating sets before relying on them.

RPE charts for cardio: Borg and 0–10 effort scales

“RPE” also names the effort scales used for running, cycling and other aerobic exercise. Gunnar Borg's original scale rates exertion from 6 to 20, numbers chosen to roughly match heart rate, and he later added a category-ratio scale, the CR10. The CDC describes a plain 0–10 version: 0 is the effort of sitting, 10 is maximal effort, 5–6 is moderate and vigorous effort starts at 7–8.

These scales rate how hard the work feels overall. They are not tied to reps in reserve or to a percent of 1RM, so the calculator above does not use them.

Questions

How do I figure out my RPE?

Right after the set, ask how many more good reps you could have done. None left is RPE 10, one is RPE 9, two is RPE 8 and three is RPE 7, the reps-in-reserve scale of Zourdos and colleagues (2016). Enter the set in the calculator above to turn it into an estimated 1RM.

What does 7 RPE feel like?

RPE 7 is a set you finish with about three reps left. On the RTS chart a single at RPE 7 is 89.2% of 1RM and a set of 5 at RPE 7 is 78.6%.

How much is 8 RPE?

RPE 8 means two reps left. As a percent of 1RM it depends on the reps: 92.2% for a single, 86.3% for 3 reps, 81.1% for 5 and 73.9% for 8 (RTS chart).

How do I explain RPE to a beginner?

Ask them to count the reps they had left: 10 means none, 9 means one, 8 two, 7 three. Helms and colleagues suggest that new lifters first test their ratings, by rating a set and then taking the same load to failure, before they base loads on RPE.