RIR (Reps in Reserve)
RIR, or Reps in Reserve, is the number of reps a lifter could have completed with good form when a set ended. 0 RIR is failure, 2 RIR means two reps were left. Coaches prescribe it to control how close to failure each set goes.
RIR: what is it?
Reps in Reserve answers one question at the end of a set: how many more could you have done? It is the mirror image of RPE. Where RPE rates effort on a 1-to-10 scale, RIR counts the reps that were left in the tank. Because counting is more concrete than rating, RIR is often the first proximity-to-failure tool a coach teaches, and it translates directly into a load decision for the next set.
The RIR scale and how it maps to RPE
RIR and RPE describe the same set from two directions, so the conversion is fixed: RIR equals 10 minus RPE. Anything above 4 RIR is usually written as "4+" because nobody can reliably count six reps left.
| RIR | Equivalent RPE | What the set looked like |
|---|---|---|
| 0 | 10 | Last rep was the last possible rep. Technical failure. |
| 1 | 9 | One more rep was there, and it would have been a grind. |
| 2 | 8 | Two clean reps left. Bar slowed noticeably on the last rep. |
| 3 | 7 | Three reps left. Last rep slower than the first but not a fight. |
| 4+ | 6 or lower | Comfortable. Warm-up, technique or deload territory. |
When to prefer RIR over RPE
RIR wins with beginners and with anyone who tends to answer "how hard was that?" with how tired they feel. Asking "how many more could you have done?" pulls the answer back to the set itself. It also wins on moderate-rep work (6 to 15 reps), where the difference between two and three reps left is something a lifter can actually feel.
RPE is the better tool on heavy singles and doubles, where "reps left" stops making sense: a near-maximal single at RPE 9.5 is not "half a rep in reserve", it is a rating of how close the attempt was. RPE also carries over to conditioning and cardio, where there are no reps to count. Many coaches use both: RIR on the accessory and hypertrophy work, RPE on the top sets of the main lifts.
Typical RIR targets by training phase
The targets below are standard practice, not rules. The principle behind them is that stimulus rises as a set approaches failure, but so does fatigue and the risk of technique breaking down. Compound lifts generally get a slightly larger reserve than isolation and machine work.
| Phase or goal | Typical RIR | Why |
|---|---|---|
| Technique learning | 4-5 | Form has to stay identical rep to rep. |
| Hypertrophy accumulation | 1-3 | Close enough to failure to recruit the most fibers, with room to repeat it across the week. |
| Strength (heavy compounds) | 2-4 | Bar speed and positions matter more than squeezing out reps. |
| Peaking or testing | 0-1 | Short blocks only, then back off. |
| Deload | 4+ | Keep the pattern, remove the fatigue. |
Common mistakes
Most lifters overestimate their reserve. A set called "3 RIR" is frequently a 1 RIR set, or sometimes a 5 RIR set; the guess is only reliable once the client has been taken to real failure on that exercise at least once. Recalibrate every few weeks by running one set of an accessory exercise past the prescribed RIR to see how many reps were actually there.
The second mistake is treating 0 RIR as the default. Grinding every set to failure inflates fatigue faster than it adds stimulus, and it wrecks the next exercise in the session. Reserve 0 RIR for the final set of an isolation movement or for a planned test.
Key takeaways
- RIR counts the reps left at the end of a set; RIR equals 10 minus RPE.
- It is the more concrete tool for beginners and for moderate-rep work; RPE fits heavy singles and conditioning better.
- Most productive hypertrophy sets sit at 1 to 3 RIR, heavy compounds at 2 to 4, deloads at 4 or more.
- Lifters overestimate their reserve until they have felt real failure; recalibrate regularly.
Frequently asked questions
What does 2 RIR mean?
2 RIR means the lifter ended the set with two more good reps available. It is the same as RPE 8. The set was hard, the last rep visibly slowed down, but there was no grinding. For most hypertrophy work, 1 to 3 RIR is the range coaches aim for on the majority of sets.
Is RIR or RPE better for beginners?
RIR, in most cases. Counting reps left is more concrete than rating effort, so beginners give more consistent answers. The catch is the same for both: the client needs to have experienced real failure on a safe exercise once, otherwise every estimate is a guess. After that first reference, both tools work.
How do I calculate the weight from an RIR target?
Start from a recent set. If the client did 8 reps at 80 kg and reported 2 RIR, that weight is right for "8 reps at 2 RIR". To prescribe 8 reps at 3 RIR, take a little off; at 1 RIR, add a little. Small adjustments of 2 to 5 percent are usually enough. A 1RM calculator gives a rough starting point for a new exercise.
Updated August 28, 2026
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