Calculator
RPE and RIR calculator
Turn how hard a set felt into a percentage of your max, and back again. RPE 8 is two reps in reserve, and the chart says what that weighs.
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81.1
81.1% of max ·2 in reserve
Percent of one rep max, by reps and RPE
| Reps | 10 | 9.5 | 9 | 8.5 | 8 | 7.5 | 7 | 6.5 | 6 |
|---|---|---|---|---|---|---|---|---|---|
| 1 | 100 | 97.8 | 95.5 | 93.9 | 92.2 | 90.7 | 89.2 | 87.8 | 86.3 |
| 2 | 95.5 | 93.9 | 92.2 | 90.7 | 89.2 | 87.8 | 86.3 | 85 | 83.7 |
| 3 | 92.2 | 90.7 | 89.2 | 87.8 | 86.3 | 85 | 83.7 | 82.4 | 81.1 |
| 4 | 89.2 | 87.8 | 86.3 | 85 | 83.7 | 82.4 | 81.1 | 79.9 | 78.6 |
| 5 | 86.3 | 85 | 83.7 | 82.4 | 81.1 | 79.9 | 78.6 | 77.4 | 76.2 |
| 6 | 83.7 | 82.4 | 81.1 | 79.9 | 78.6 | 77.4 | 76.2 | 75.1 | 73.9 |
| 7 | 81.1 | 79.9 | 78.6 | 77.4 | 76.2 | 75.1 | 73.9 | 72.3 | 70.7 |
| 8 | 78.6 | 77.4 | 76.2 | 75.1 | 73.9 | 72.3 | 70.7 | 69.4 | 68 |
| 9 | 76.2 | 75.1 | 73.9 | 72.3 | 70.7 | 69.4 | 68 | 66.7 | 65.3 |
| 10 | 73.9 | 72.3 | 70.7 | 69.4 | 68 | 66.7 | 65.3 | 64 | 62.6 |
| 11 | 70.7 | 69.4 | 68 | 66.7 | 65.3 | 64 | 62.6 | 61.3 | 59.9 |
| 12 | 68 | 66.7 | 65.3 | 64 | 62.6 | 61.3 | 59.9 | 58.6 | 57.4 |
Read down for the reps and across for how the set should feel. RPE 8 at five reps is about 81 percent, which is the same set as five with two reps in reserve.
How it works
RPE in lifting means how close a set came to failure. Ten is a set with nothing left. Nine means one more rep was available, eight means two, and so on down. Reps in reserve says the same thing from the other end, so RPE 8 and two reps in reserve are one number written two ways.
The chart maps reps and RPE onto a percentage of your one rep max. Give it a max and it prints the weight for any combination; give it a weight and how the set felt, and it works backward to the max that implies.
A set of five at RPE 8 sits at about eighty-one percent. On a 150 kilo squat that is 122 kilos, and if five reps at 122 actually felt like a nine, the chart says your max is nearer 143 than 150.
The point of programming by RPE rather than by fixed percentages is that your max moves daily. Sleep, food and the session before all change what eighty percent feels like, and a program written in percentages ignores every one of them. Writing five at RPE 8 asks for the same relative effort whatever kind of day it is.
Judging RPE takes practice, and the error runs one way. Almost everyone calls sets harder than they are, so early RPE 9s are usually sevens. Take a few sets genuinely to failure at some point, so you know what ten feels like and have something to measure the rest against.
Questions
- What does RPE mean for lifting?
- How close the set came to failure. RPE 10 means you could not have done another rep, RPE 9 means one more was there, RPE 8 means two. It is reps in reserve counted from the other end.
- What is the difference between RPE and RIR?
- None, except the direction. Reps in reserve is ten minus the RPE, so RPE 8 and 2 reps in reserve describe the same set.
- How accurate is judging your own RPE?
- Poor at first and better with practice. Beginners routinely call a set RPE 9 when four reps were left, which is why the chart is a guide for picking weights rather than a measurement.
- Can I use it to estimate a max?
- Yes. A set of five that felt like RPE 8 sits at about eighty-one percent of your max, and the tool works that backward into an estimated one rep max.