RIR vs RPE: Reps in Reserve vs RPE Scale Explained
I trained "hard" for two years before I learned what hard actually meant
For my first two years of lifting, my training journal had two columns: weight and reps. That was it. If you had asked me how hard a set was, I would have said "hard" or "easy" - and meant nothing measurable by either word.
The wake-up call came from a coach who watched a video of my "hard" set of 8 squats. He said, "You had four reps left. That is a moderate set, not a hard one." I argued. I had grunted. The bar had moved slowly. It felt heavy. Hard, right?
He had me retest. Same weight, same target. He told me to keep going past 8 until my form broke down. I hit 12 reps before I genuinely could not do another one. Four reps in reserve, exactly as he had called it. My subjective sense of effort was off by 50%.
That is the gap RIR and RPE close. RIR (reps in reserve) and RPE (Rate of Perceived Exertion) are the two effort-tracking scales used in structured strength training - and knowing which to use changes how you program every working set. They are calibration tools - ways to measure the gap between what you feel and what you can actually do. Use them right and your training becomes precise. Use them wrong, or skip them entirely, and you are guessing at every working set.
What is the RPE scale
RPE stands for Rate of Perceived Exertion. The scale runs from 1 to 10:
| RPE | Meaning |
|---|---|
| 10 | Maximal effort. Could not have done another rep. |
| 9.5 | Could not have done another rep, but maybe with a slight grind. |
| 9 | Could have done 1 more rep. |
| 8.5 | Definitely could have done 1, maybe 2 more. |
| 8 | Could have done 2 more reps. |
| 7.5 | Could have done 2-3 more reps. |
| 7 | Could have done 3 more reps. |
| 6 | Could have done 4 or more reps. |
| 5 and below | Warm-up territory. |
RPE was originally developed for endurance training in the 1960s by Gunnar Borg, then adapted to strength training by Mike Tuchscherer in the 2000s. The strength training version focuses on the 6-10 range because anything below 6 is too light to drive adaptation.
The advantage of RPE: it captures the full effort experience. A grinding rep at the end of a set with shaking limbs and labored breathing reads differently than a clean rep at the same weight on a fresh day, even if the rep count is identical.
The disadvantage: it requires more interpretation. The difference between RPE 8 and RPE 8.5 is subtle, and beginners struggle to differentiate. RPE works well for experienced lifters with calibrated effort awareness. For most others, there is a simpler, more practical alternative.
What is RIR: the practical version
RIR stands for Reps In Reserve. Instead of a 1-10 scale, you ask one question after a set: "How many more reps could I have done with good form?"
| RIR | Meaning |
|---|---|
| 0 | Could not have done another rep. |
| 1 | Could have done 1 more rep. |
| 2 | Could have done 2 more reps. |
| 3 | Could have done 3 more reps. |
| 4+ | Submaximal training, warm-up, or recovery work. |
RIR is just RPE simplified. RPE 10 = RIR 0. RPE 9 = RIR 1. RPE 8 = RIR 2. RPE 7 = RIR 3. The math is identical; the framing is different.
The advantage of RIR: it asks a concrete, countable question. "How many more could I do?" has an answer. "What is my rate of perceived exertion?" requires more abstract self-evaluation.
The disadvantage: it loses the subtlety between effort levels. RPE 8 and RPE 8.5 collapse into RIR 2 - no distinction. For most lifters, that loss of granularity is not actually a problem. The simpler scale gets used more consistently.
RIR vs RPE: which one to use
The honest answer: for most lifters, RIR is the better choice. Here is why.
| Factor | RIR | RPE |
|---|---|---|
| Cognitive load | Low (count reps in reserve) | Higher (interpret effort scale) |
| Calibration time | 2-3 weeks | 4-8 weeks |
| Granularity | Whole numbers (0, 1, 2, 3) | Half-points (8, 8.5, 9) |
| Strength training fit | Excellent | Excellent |
| Hypertrophy training fit | Excellent | Good (but RIR is faster to log) |
| Endurance training fit | Limited | Excellent |
| Best for beginners | Yes | No |
| Best for advanced | Either | Either |
Use RIR when:
- You are new to tracking effort
- You train primarily for hypertrophy or general strength
- You want simpler logging during workouts
- You want a number that translates directly to a programming decision
Use RPE when:
- You have already calibrated your effort sense over months
- You train for competitive powerlifting and need precise top-set execution
- You run programs that prescribe specific RPE targets
- You want to capture the difference between RPE 8 and RPE 8.5 (e.g., for percentage-based programming)
For 90% of lifters, RIR wins. It is faster, simpler, and produces nearly the same training decisions as RPE for the same input data.
The calibration problem: why most lifters underestimate effort
The biggest issue with both RIR and RPE is not the scale. It is that lifters consistently overestimate how hard their sets are - especially in the first few months of using the scales.
A 2017 study (Hackett et al., Journal of Strength and Conditioning Research) tested experienced lifters' RIR estimates against actual repetition maxes. Experienced lifters' estimates were within 1-2 reps of accuracy at low RIR values (0-1), but at higher RIR values (3-5), the estimates drifted by as many as 4-6 reps. In other words: when lifters thought they had 3 reps left, they often had 6-9.
This calibration error has a specific direction. Lifters underestimate their capacity, especially when set intensity feels subjectively high. The grunt and slow rep velocity are mistaken for proximity to failure when they are actually just cues from the working effort itself.
Three calibration tests fix this:
Test 1: AMRAP your "RIR 2" set
Pick a moderate weight where you would normally stop at "RIR 2" for a set of 8. Instead, keep going until form breaks. Record actual reps to failure.
If you stopped at 8 thinking you had 2 in reserve and went to 14 reps, your RIR estimate was 6 - not 2. That is the gap. Recalibrate accordingly.
Test 2: Track AMRAP rep counts
Programs like 5/3/1 prescribe AMRAP top sets at specific percentages. The expected reps at each percentage are well-documented:
| % of 1RM | Expected reps to failure |
|---|---|
| 95% | 2-3 |
| 90% | 3-5 |
| 85% | 5-7 |
| 80% | 7-10 |
| 75% | 9-12 |
| 70% | 11-15 |
If you AMRAP at 85% and hit 4 reps, your true 1RM is lower than you think. If you hit 10, your training max is set conservatively. Either way, the AMRAP calibrates your sense of effort against external benchmarks.
Test 3: Video review
Film a "hard" set. Watch the bar speed on your last "RIR 2" rep. If the bar is still accelerating, you had more than 2 in reserve. If the bar is grinding to a near-stop, you had 0-1.
Bar speed is the cleanest objective measurement of proximity to failure. The set you thought was RIR 2 with smooth bar movement was probably RIR 4-5. The set you thought was RIR 2 with the bar visibly slowing was probably RIR 0-1.
After two or three calibration sessions, your RIR estimates start matching reality. From there, the data is reliable.
How to log RIR per set without slowing your workout
The friction of effort tracking is real - and friction kills logging consistency. Here is how to keep it fast.
Log RIR only on the last set
The first 1-2 sets of a working set are usually well below failure. RIR 4 on set 1 of a 3-set workout is not interesting data - it is just "the warm-up to the real set." The last set is where RIR matters because that is where the proximity-to-failure decision drives next-week's programming.
You can simplify further: log RIR on the working set that pushes closest to failure. For a typical 3 x 6 at moderate weight, that is set 3.
Use whole numbers
RIR 1.5 is overthinking it. Round to whole numbers (0, 1, 2, 3). The accuracy loss is minimal and the logging speed gain is significant.
Log immediately after the set
The longer the gap between the set and the RIR estimate, the more your memory drifts. Log RIR within 10 seconds of racking the bar. After two minutes of rest, your sense of how hard the set was is already biased by recovery.
Use a tool that makes it one-tap
The difference between a 30-second logging step and a 3-second logging step is whether you actually do it consistently. A one-tap RIR selector means RIR makes it into every set log.
Common RIR and RPE mistakes
1. Tracking RIR but not using it
Logging RIR without using it to drive programming decisions wastes the data. The point of RIR is to know when to add weight. If your last set was RIR 1-2 for two consecutive sessions, you have earned a weight increase. If your last set was RIR 0 with a missed rep, you need to back off.
2. Using RIR when you have not calibrated
If your RIR estimates are off by 3-4 reps, the data is not just wrong - it is misleading. Calibrate first, then trust the numbers.
3. Mixing scales
Pick RIR or RPE. Do not switch between them mid-block. The two scales are interconvertible but switching breaks the trend lines in your data.
4. Logging RIR for warm-ups
Warm-up sets are RIR 4+ by design. Logging "RIR 5" for a warm-up adds noise to your data without adding signal. Save RIR for working sets only.
5. Treating RIR as a goal
RIR 0 every set is not a target. It is a sign of overreaching. Programs that work over months prescribe RIR 1-3 on most sets and RIR 0 only on AMRAP top sets. Aiming for RIR 0 every workout burns out the system that drives progressive overload.
6. Comparing RIR across exercises uncritically
RIR 2 on a squat does not equal RIR 2 on a lateral raise. Compounds have a steeper proximity-to-failure curve than isolation exercises. Use RIR within the same exercise to drive decisions, not across different exercises.
How RIR drives progressive overload decisions
RIR is not just a label. It is the signal that tells you when to increase weight, when to add reps, and when to back off.
The framework is simple:
| Last set RIR | Action |
|---|---|
| 0 with missed reps | Reduce weight or reps next session |
| 0-1 hitting target | Stay, retest next session |
| 1-2 hitting target | Stay or increase weight if pattern holds |
| 2-3 hitting target | Increase weight or push for more reps |
| 4+ hitting target | Weight is too light, increase by larger jump |
This is the engine of double progression and the core mechanic of most well-designed plans. Without RIR, you are guessing at when to progress. With RIR, the decision is data-driven and reproducible.
The same framework applies whether you are running PPL, 5/3/1, or any other structured plan. The plan provides the structure. RIR provides the feedback.
How to use RIR in your workouts starting tomorrow
You do not need a six-week ramp to start using RIR. The basic implementation takes one session.
Session 1: Calibrate. Pick one main exercise. Do your normal working sets at your usual weight. On the last set, instead of stopping at your planned reps, push to actual failure. Note the gap between what you thought your RIR was and what it actually was.
Session 2: Log RIR for working sets. Use the calibrated estimate from session 1 as your reference point. Log RIR on every working set across all exercises. Keep it to whole numbers.
Sessions 3-6: Recalibrate weekly. If you can, do one AMRAP-to-failure set per week to keep your RIR sense calibrated. After 4-6 weeks, your estimates will be consistently within 1 rep of reality.
Session 7+: Use RIR to drive decisions. When the last set of an exercise hits RIR 1-2 for two consecutive sessions at the prescribed reps, increase the weight on that exercise. When the last set hits RIR 0 with missed reps, reduce. The system runs itself.
Frequently asked questions about RIR and RPE
Should I use RIR for every exercise?
For working sets on every exercise, yes. The data only becomes useful when you have a continuous record. Skipping isolation exercises means you cannot diagnose whether your accessories are driving fatigue or recovery is breaking down.
How accurate is RIR for estimating my one-rep max?
The relationship between RIR and 1RM is well-mapped: weight x (1 + reps/30) gives a rough estimate. If your last set was 80 kg x 8 with RIR 1, your estimated 1RM is roughly 80 x (1 + 9/30) = 104 kg. Within 5-10% accuracy for most lifters at most weights. We covered this in the progressive overload guide.
Is RIR the same as effort?
Closely related, but not identical. RIR measures proximity to failure. Effort includes mental engagement, breathing, and arousal. A set can be high effort but low proximity to failure (think of a max weight at a low rep target). For training decisions, proximity to failure is what matters.
Can RIR replace tracking weight and reps?
No. RIR is a third data point alongside weight and reps. All three together tell the full story of a set. Two of three is incomplete data.
Should beginners use RIR?
Yes. The earlier you calibrate effort awareness, the more reliable your data is over the long run. Beginners who learn to estimate RIR from month one progress faster than beginners who only track weight and reps.
What if I cannot tell the difference between RIR 1 and RIR 2?
Log it as RIR 1-2 or pick the more conservative number (2). Over time, calibration tests will sharpen your sense. Even rough RIR data is more useful than no RIR data.
Tracking RIR and RPE in Pully
The biggest practical issue with RIR and RPE is logging speed. Adding a third data point to every set in a notebook or spreadsheet adds friction that kills consistency.
Pully makes RIR a one-tap addition per set.
One-tap RIR selector - log weight, reps, and RIR per set in seconds. The interface stays out of your way during the session.
Per-variant RIR history - your RIR on flat bench is tracked separately from your RIR on incline dumbbell. Each variant builds its own progression curve. We covered why this matters in our bench press progression guide. For a full picture of how effort data fits into your training history, see the gym progress tracking guide.
Estimated 1RM from your sets - every weight, reps, RIR combination generates an estimated 1RM automatically. Watch the trend line, not just the tested numbers.
Progressive overload signals - when your RIR drops at the same weight (your 80 kg x 6 used to be RIR 2, now it is RIR 0), Pully surfaces the signal. Use it as the trigger for deload decisions or weight increases.
Week-over-week comparison - see how RIR is trending across exercises. Improving (RIR rising at same weight)? You are getting fitter. Declining (RIR dropping at same weight)? Fatigue is accumulating.
Download Pully from the App Store and start logging RIR alongside weight and reps in your next session.
Your RIR starter checklist
Step 1: Pick RIR or RPE. Default to RIR unless you have a specific reason to use RPE.
Step 2: Run a calibration session. AMRAP one working set this week and compare your estimated RIR to actual reps to failure.
Step 3: Log RIR on every working set. Whole numbers (0, 1, 2, 3). Logged within 10 seconds of finishing the set.
Step 4: Use RIR to drive decisions. When your last set is RIR 1-2 for two consecutive sessions, increase weight. When it is RIR 0 with missed reps, reduce.
Step 5: Recalibrate every 4-6 weeks. Run a new AMRAP test and check whether your RIR estimates still match actual reps to failure.
Step 6: Trust the data over the feeling. When your RIR data says you are ready to add weight but the set "felt hard," trust the data. The feeling is biased; the data is not.
RIR is not glamorous. It is just the cleanest way to know whether your training is actually working. Add it to every working set, calibrate honestly, and your progression decisions stop being guesses.
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