RPE vs RIR: What They Mean and How to Log Them

Quick answer: RPE (rating of perceived exertion) scores how hard a set felt on a 1 to 10 scale. RIR (reps in reserve) counts how many reps you could still have done. In lifting they are two views of the same thing: RPE 8 equals 2 RIR, RPE 9 equals 1 RIR, and RPE 10 equals 0 RIR, a set taken to failure.

Your program says "3x5 @ RPE 8" and you stare at it in the squat rack, not entirely sure whether that means heavy, very heavy, or the kind of heavy where someone has to help you.

Meanwhile your friend logs everything as "2 RIR" and swears it is simpler.

They are describing the same set. The whole RPE vs RIR question comes down to direction: one counts effort, the other counts reps left in the tank.

What is RPE in weight training?

RPE is a 1 to 10 rating of how hard a set felt. The version lifters use is not the old cardio scale that ran to 20. It is a resistance training scale anchored to how many reps you had left.

That anchoring is what makes it usable. "Felt like an 8" is vague. "Two reps left" is something you can actually judge in the moment.

The modern version was formalised by Zourdos and colleagues in the Journal of Strength and Conditioning Research, who built an RPE scale defined by reps in reserve and tested it against bar speed. They found strong inverse relationships between average velocity and RPE in both experienced squatters (r = -0.88) and novices (r = -0.77): as the bar slowed, ratings climbed, which is exactly what a valid effort scale should do.

What is RIR, and how is it different?

RIR is the raw count: how many more reps could you have completed with good form? Nothing else, no scale, no interpretation.

Stop a set of eight when you had three good reps left and you just did 3 RIR.

The difference is direction, not substance. RPE asks "how hard was that?" and RIR asks "how much was left?" You can convert between them without losing information.

So which should you write down? For most people, RIR is easier to learn because it asks a concrete question. RPE is easier to program with, because coaches write "@8" faster than "leave 2 in the tank". Learn RIR, log whichever your program speaks.

Are lifters actually any good at judging RIR?

Honestly? Not at first. This is the part most articles skip, and it matters more than the definitions.

In a study of 141 participants published in PeerJ, Steele and colleagues had people predict how many reps they could complete before taking sets to genuine failure. Almost everyone underpredicted, meaning they had more reps left than they thought.

Untrained participants were off by roughly four to five reps. Experienced and expert lifters were off by only one to two. The authors concluded that RIR scales should be used cautiously by less experienced trainees.

The practical takeaway is not "ignore RPE". It is that your first months of RIR ratings are guesses, and guesses improve with reference points.

The fastest way to build those reference points is to take a few sets to true failure on safe exercises (a machine press, a leg extension, a dumbbell curl) and compare what you predicted with what happened. Do that a handful of times and your 2 RIR starts meaning something.

When should you use RPE instead of fixed percentages?

Use RPE on days your body did not read the program. A percentage says 80% of your one rep max regardless of whether you slept four hours or eight.

RPE self-corrects. On a strong day, 80% might sit at RPE 7 and you add weight. On a bad day it feels like a 9, and stopping there is the right call.

If you want a starting number to build percentages from, plug your best recent set into the one rep max calculator, then use RPE to adjust the day's load around it.

Percentages still win for peaking and for beginners. A new lifter has neither the reference points nor the technical consistency to rate effort accurately, which is exactly what the PeerJ data showed. Run linear progression first, add RPE once the numbers stop being automatic.

How do you write RPE and RIR in a workout log?

Attach the rating to the set, not the workout. A session-level "felt hard" tells you nothing three months later.

Common shorthand, all of which people actually use:

• squat 100kg 5x3 @8 for three sets of five at RPE 8.
• squat 100kg 5,5,5 (2 RIR) when you prefer reps in reserve.
• bench 80kg 8,8,7 @8/@9/@10 when the effort climbed set to set.

That last format is the useful one. Three sets rarely feel identical, and the drift from 8 to 10 across a session is the clearest signal that your weight selection or rest between sets needs adjusting.

If the notation itself is new to you, workout shorthand explained covers the rest of the vocabulary.

Why do effort ratings usually stop getting logged?

Effort ratings are the first thing people stop logging. Not because they are useless, but because they are one more field.

In a structured gym app, RPE lives behind a tap, then a scroll, then a confirm, all while your rest period is running out. In a notebook, it is two characters. Guess which one survives month three.

Here is how the options really compare:

Gym Note Plus exists to close that last gap. You write the set the way you already would, including the effort tag, and it reads the text into a structured log:

• Your shorthand, understood. bench 80kg 8,8,7 @9 becomes exercise, weight, reps, and effort.
• Last session on screen. You know what you lifted and how hard it felt before you load the bar.
• Charts from text. Weight and volume trends build themselves from lines you typed in seconds.
• Nothing to configure. No templates to set up before your first set.

Want to see it before installing anything? Paste a few lines of your own notes into the free notes to workout translator.

RPE and RIR describe the same set from opposite ends. Pick the one you will still be writing down in six months.

A simple starting plan

1. Pick one scale this week. RIR if you are new to effort ratings, RPE if your program is already written in it.
2. Calibrate three times. Take one safe isolation set to genuine failure, predict first, then compare.
3. Rate every working set, not just the top set, using two characters at the end of the line.
4. Cap most sets at RPE 8 or 2 RIR for your main lifts, leaving failure for isolation work.
5. Review after four weeks. If your RPE at a fixed weight is falling, you are getting stronger. Add load.

Frequently Asked Questions

What does RPE 8 mean in lifting?

RPE 8 means you finished a set with roughly two good repetitions still available. On the reps in reserve based RPE scale used in resistance training, RPE 10 is failure with zero reps left, RPE 9 leaves one rep, and RPE 8 leaves two. The bar is noticeably slowing but form is still solid.

Is RIR better than RPE?

Neither RIR nor RPE is better; they measure the same effort from opposite directions. RIR is usually easier for newer lifters because counting remaining reps is a concrete question. RPE is more compact for written programs, which is why coaches write "@8" rather than "leave two reps in reserve" in a training plan.

Should beginners use RPE?

Beginners should treat RPE as a skill to build rather than a tool to program with. Research published in PeerJ found untrained lifters underpredicted their reps to failure by roughly four to five repetitions, compared with one to two for experienced lifters. Start with fixed loads and linear progression, then layer RPE on once technique is consistent.

How do you write RPE in a workout log?

Write the rating at the end of the set line so it stays attached to that specific set. Common formats are squat 100kg 5x3 @8 for a whole exercise, or bench 80kg 8,8,7 @8/@9/@10 when effort climbed set to set. Per-set ratings are far more useful later than a single note for the whole session.

Does training at RPE 10 build more muscle?

Training at RPE 10, meaning to failure, is not required for muscle growth and adds meaningful fatigue. Most lifters get the majority of the stimulus stopping around RPE 8 to 9, which leaves one to two reps in reserve, and reserve true failure for isolation exercises where the recovery cost and injury risk are lowest.

Final Takeaways

• RPE and RIR are the same measurement. RPE 8 equals 2 RIR, RPE 9 equals 1 RIR, RPE 10 equals failure.
• Beginners underestimate by 4 to 5 reps. Calibrate with a few honest sets to failure before trusting your ratings.
• Use RPE to adjust for the day, and percentages or linear progression when you need a fixed target.
• Rate every working set, and watch the drift from set one to set three.
• Falling RPE at the same weight is progress. That is your cue to add load.
• Log it in two characters. If rating a set takes longer than that, you will stop doing it.