RIR explained: how to use reps in reserve to log your effort
What RIR (reps in reserve) means, how it relates to RPE, how to rate it honestly and how to log it on your top sets to keep progress on track.
Key takeaways
- RIR (reps in reserve) is how many more clean reps you could have done when you stopped the set.
- RIR 0 means failure, RIR 2 means two reps left; RPE 8 is roughly RIR 2.
- Most lifters underestimate how many reps they have left, especially on lighter, higher-rep sets.
- Logging RIR on top sets shows whether your effort is drifting, which is often the hidden cause of a plateau.
Two lifters both do “5 reps at 100 kg”. One stopped with three clean reps left; the other ground out the fifth rep with nothing left. On paper, the sessions are identical. In reality, they are completely different. RIR is the number that tells them apart.
What does RIR mean?
RIR stands for reps in reserve: how many more clean reps you could have done when you ended the set.
| RIR | What it means | RPE equivalent |
|---|---|---|
| 0 | Failure: no more clean reps possible | 10 |
| 1 | One more rep was possible | 9 |
| 2 | Two more reps were possible | 8 |
| 3 | Three more reps were possible | 7 |
| 4+ | Comfortable, far from failure | 6 or less |
The scale was popularised for lifting by researchers who adapted the classic effort scale (RPE) so that each point matches a rep left in the tank.
RIR vs RPE: which should you use?
They describe the same thing from two angles. RPE asks “how hard was that, out of 10?”; RIR asks “how many reps did you have left?”. Many lifters find RIR easier because it is a concrete count, not a feeling.
If your coach writes “RPE 8”, read it as “stop with about two reps left”.
How to rate RIR honestly
Most people underestimate what they have left, especially on sets of 10 or more. A few habits help:
- Rate immediately after the set, before you rest and forget how the last rep felt.
- Judge by bar speed. When the last rep slows down clearly, you are usually within one or two reps of failure.
- Calibrate now and then. On a safe exercise (machine, dumbbells with a spotter), take a set to failure and compare with your guess.
- Rate top sets at minimum. Warm-ups do not need a number.
Why logging RIR prevents plateaus
Without RIR, your log only shows load and reps. If your effort slowly drifts down, the log looks like a plateau even though you are simply working less hard. If effort drifts up toward grinding reps, fatigue builds and the plateau is real.
Recording RIR on top sets shows both drifts. It also helps you on bad days: after a short night, adding one rep in reserve keeps the session productive without digging a hole. See sleep and strength training.
How RIR fits progressive overload
A simple rule many lifters use: when you hit all your sets at the target reps with more RIR than planned, add weight next time. If RIR keeps falling at the same load, look at recovery before blaming the program. See how to track progressive overload.
How rythme helps
rythme logs RIR on any set, next to warm-ups, dropsets, rest-pause, left and right sides and supersets, with a rest timer, and it works offline. Your effort history sits next to your sleep and meals, so when RIR keeps dropping at the same load, you can see what changed outside the gym.
FAQ
What is the difference between RIR and RPE?
RIR counts the reps you had left. RPE rates effort on a 1–10 scale. In the lifting version of RPE, RPE 10 is RIR 0, RPE 9 is RIR 1 and RPE 8 is RIR 2.
What RIR should I train at?
Many programs keep most working sets around RIR 1 to 3. Your program sets the target; your job is to rate honestly and log it.
Is RIR accurate?
It gets more accurate with practice and on heavier sets close to failure. Rating every top set and occasionally testing a set to a safe failure improves your calibration.
Sources
- Zourdos et al. (2016). Novel resistance training-specific rating of perceived exertion scale measuring repetitions in reserve. Journal of Strength and Conditioning Research.
- Helms et al. (2016). Application of the repetitions in reserve-based rating of perceived exertion scale for resistance training. Strength and Conditioning Journal.
This article is general information, not medical advice. Talk to a qualified professional about your own health.
