RPE Calculator and RIR Chart for Lifting

What RPE Means in the Gym

RPE stands for rating of perceived exertion. In lifting, it’s a rating from 1 to 10 that you give a set once it’s done. At 10, you had nothing left. Each point lower, down to 7, means one more rep you could still have done. Those are your reps in reserve.

A program that says “3 × 5 at RPE 8” calls for three sets of 5 reps with a weight you could lift 7 times.

Half points mark the in-between. RPE 8.5 means 1 to 2 reps in reserve, and RPE 7.5 means 2 to 3. RPE 9.5 is the exception: you couldn’t have done another rep, but you could have gone a little heavier.

Below 7, the scale stops counting reps one at a time. RPE 5 and 6 together cover 4 to 6 reps in reserve, and from 1 to 4 the rating describes light effort or almost none. The scale is mostly used from 7 to 10, because you’re best at judging what you have left when you’re close to failure.

This scale first showed up in research in 2016, in a study of 29 people on the squat. The chart at the top of the page follows it.

RIR: Reps in Reserve

RIR stands for reps in reserve. It’s the number of reps you could still have done at the end of the set. From RPE 7 to RPE 10, you can get one from the other, because the two add up to 10:

• 0 RIR is RPE 10.
• 1 RIR is RPE 9.
• 2 RIR is RPE 8.
• 3 RIR is RPE 7.

So “4 × 8 at 2 RIR” and “4 × 8 at RPE 8” call for the same set. The rule stops at RPE 7. Below that, the scale gives a range, not a number.

RPE Chart: Percentage of 1RM by Reps

Find the row for your reps and the column for your RPE. Where they meet is the percentage of your 1RM (the heaviest weight you can lift once) to use. With a 1RM of 200 lb, 5 reps at RPE 8 is 81%, or 162 lb.

The same RPE isn’t the same percentage from one row to the next. At RPE 8, 1 rep is 91% of your 1RM, and 8 reps is 75%. “RPE 8 = 85%” with no rep count doesn’t mean anything.

Half points fall halfway between their two neighbors:

A dash marks a set that adds up to more than 10 reps once you count the reserve: 8 reps at RPE 7 is 8 done plus 3 in reserve, for 11. Past 10, the seven formulas in the 1RM calculator give different answers. For those sets, the calculator at the top of the page shows a weight with “≈” in front of it, with the lowest and highest of the seven.

How to Calculate Your 1RM from RPE

A set stopped short of failure counts as a longer set taken all the way: 5 reps with 2 in reserve uses the same weight as 7 reps to failure. Published charts are built on this idea. So to estimate a 1RM, you add the reps in reserve to the reps you did, then apply the Epley formula:

1RM = weight × (1 + (reps + RIR) ÷ 30)

Example: 175 lb for 5 reps at RPE 8 leaves 2 in reserve, so the estimate is 175 × (1 + 7 ÷ 30) = 215.8 lb. The same set taken to failure, at RPE 10, would give 175 × (1 + 5 ÷ 30) = 204.2 lb.

Going the other way, the weight to use is your 1RM times the percentage from the chart. With a 1RM of 225 lb, 8 reps at RPE 8 is 75%, or 168.8 lb.

Log chose this method: count the reserve, then apply the Epley formula. At RPE 10, with nothing in reserve, that’s the same calculation the 1RM calculator uses. Log found no study that checks these percentages against a measured 1RM.

Why Two RPE Charts Give Different Numbers

Two other charts are widely used. Like this page, they count reps in reserve as reps done. The only difference is the percentage they assign to each number of reps.

• The Reactive Training Systems chart, the most widely copied, comes from Mike Tuchscherer’s company. Its author recommended building your own, and advised against using it to calculate a 1RM.
• The chart by Helms and his coauthors, published in 2016, is built on three measurements taken from 15 experienced lifters on the squat. Its other values are estimates. It covers 1 to 8 reps and RPE 7 to RPE 10, and its authors asked readers not to treat it as an exact conversion.

For 5 reps at RPE 10, the first gives 86.3%, the second 85%, and this page 85.7%. Up to 10 reps, reserve included, this page’s calculation stays within 2 percentage points of each. The other two charts are just as far apart from each other.

How to Estimate Your RPE

You don’t calculate RPE. You estimate it at the end of the set, by counting the reps you could still have done. Studies have measured this estimate by asking lifters to say how many reps they had left, then to keep going to failure.

• You think you’re closer to failure than you are. In a 2022 review that pooled 12 studies and 414 people, lifters underestimated what they had left by about one rep on average.
• The estimate is more accurate close to failure. Among 81 adults, the error was about one rep when they had 0 to 5 left, and more than two when they had 7 to 10 left.
• Long sets are harder to judge. On squat sets averaging 16 reps, trained men were off by 2 reps when they said they had 1 left, and by 5 when they said they had 5.
• Later sets are easier to judge than the first, according to the 2022 review.
• Studies disagree on whether experience helps. In the 2022 review, trained lifters didn’t estimate better than the rest. Other studies found experienced lifters more accurate, especially when rating a 1RM attempt.

Being off by one rep in reserve shifts your estimated 1RM by about 3%. To check your rating, Helms and his coauthors suggested this: rate a set you stop short of failure, then take the next set to failure at the same weight.

RPE 10: Should You Train to Failure?

RPE 10 is failure: no more reps. Two research reviews, in 2022 and in 2023, found no clear advantage to going to failure over stopping short of it.

• In a 2024 study of 18 trained lifters, stopping 1 or 2 reps short of failure led to the same quadriceps growth over 8 weeks as going to failure.
• A 2024 analysis that pooled several studies found that muscle growth increased as sets ended closer to failure, while strength gains stayed about the same. Its authors called it exploratory.
• The American College of Sports Medicine wrote in 2026 that going to failure isn’t necessary, and that stopping 2 or 3 reps short of failure can be enough effort. It also found the evidence insufficient to set a specific RIR or RPE target.

There’s no consensus on an RPE target. And studies don’t all use the word “failure” the same way. It can mean the rep that won’t go up no matter how hard you push, or the moment you decide to stop.

RPE vs. Percentage of 1RM

A program gives its weights in one of two ways: as a percentage of 1RM (“4 × 5 at 80%”) or by effort (“4 × 5 at RPE 8”). A percentage comes from a past lift, while RPE follows how strong you are that day. And the number of reps you can do at a given percentage varies from person to person, which an effort rating accounts for.

Studies haven’t picked a winner:

• Over 8 weeks, trained men made about the same progress with weights set as a percentage of 1RM as with weights chosen to hit a target RPE.
• Over 12 weeks, 31 trained men gained more on the squat with weights adjusted by reps in reserve than with percentages set at the start.
• A 2022 review found no strength advantage for either approach, and the American College of Sports Medicine considered the data still insufficient.

The two methods work together. You start from a percentage, then use an RPE range to adjust the weight from set to set.

RPE, the Borg Scale, and Session RPE

Three scales go by the name RPE, and they don’t measure the same thing:

• The Borg scale, from 6 to 20, is the one used in endurance exercise and stress tests. It rates an overall feeling of exertion.
• Session RPE is a single rating for the whole workout, multiplied by its duration. It’s used to track training load from week to week.
• Per-set RPE, the one on this page, is a rating from 1 to 10 given at the end of a set, based on reps in reserve.

Rating perceived exertion goes back to Gunnar Borg, who published the 6-to-20 scale in 1970 and a ten-point scale, known as CR10, in 1982.

Counting the reps you have left comes from powerlifting. Research papers credit the idea to coach Mike Tuchscherer, in a manual published in 2008. In his scale, a half point marks doubt: 9.5 means you might have had one more rep. The 2016 scale, the one on this page, reads 9.5 as room for a little more weight. In 2012, a study of 17 bodybuilders showed that they could tell how many reps they had left, but their rating on a classic effort scale stayed below the top even at failure.

RPE and Log

Log is the workout tracker for iPhone that publishes this page. It doesn’t record RPE or RIR. To keep your rating, write it in the exercise’s comment: “RPE 8.”

Log does recognize sets taken to failure. Write “3 × max” in a note you import, and the sets show up as “(max)” in Log. A max set has no rep count to reach, so there’s nothing to beat next time. Log doesn’t suggest increasing the weight for it, and tells you why: “Sets taken to failure can’t support a suggestion. Leave 1–2 reps in reserve and aim for the target.” The article on progressive overload explains the rule Log applies.

In an exercise’s details, the “e1RM” (estimated 1RM) chart applies the Epley formula to the reps you did, without counting any reserve. For a set of 2 to 10 reps taken to failure, you get the same number there as on this page. For a set stopped short of failure, Log shows a lower estimated 1RM.

The conventions for weight, bar included or per dumbbell, are in the guide How to Log Sets, Reps and Weight. To review two workouts side by side, see How to Compare Workouts Without Losing the Context.

This page explains a scale and a calculation. It doesn’t replace medical advice or the supervision of a qualified professional.