RPE and RIR are two methods for prescribing and tracking training intensity based on effort rather than a fixed percentage of your max. They are closely related - in fact, RPE and RIR are mathematically linked - but each has practical advantages depending on how you train. This page explains both scales, shows how to convert between them, and helps you decide which to use.
RPE (Rate of Perceived Exertion)
Strengths
- Intuitive effort-based rating (how hard did that feel?)
- Standard in powerlifting - most programs use RPE notation
- Half-steps (7.5, 8.5) allow more granular tracking
- Used in Tuchscherer RPE chart for percentage lookups
- Better for singles and doubles where RIR is hard to judge
Limitations
- Less intuitive for beginners who struggle to rate effort
- Perceived exertion influenced by pain and discomfort, not just proximity to failure
- Harder to coach remotely - effort is subjective
Best When
Use RPE when following a powerlifting program (most use RPE notation), doing heavy singles or doubles, or looking up training percentages from a chart. RPE is the standard language of autoregulated powerlifting programming.
RIR (Reps in Reserve)
Strengths
- Very concrete - counting reps is easier than rating effort
- Easier for beginners to use accurately from day one
- Directly actionable: "leave 2 reps in reserve" is clear
- Preferred for hypertrophy work where rep ranges are higher
Limitations
- Less common in powerlifting programming
- Difficult to use on max singles or doubles
- Some programs mix RIR and RPE causing confusion
- No standard chart equivalent to the Tuchscherer RPE table
Best When
Use RIR when doing hypertrophy work with higher rep ranges (8+), when coaching beginners who find effort-rating abstract, or when following a program that specifies RIR targets. RIR is increasingly common in evidence-based hypertrophy literature.
Side-by-Side Comparison
| Attribute | RPE (Rate of Perceived Exertion) | RIR (Reps in Reserve) |
|---|---|---|
| Scale direction | 1 (easy) to 10 (max effort) | Many reps left to 0 reps left |
| Max effort value | RPE 10 | RIR 0 |
| Easy set value | RPE 6 | RIR 4 |
| Intuitive for | Effort / exertion rating | Counting remaining reps |
| Common in | Powerlifting, RPE-based programs | Hypertrophy, RTS templates |
| Originated from | Borg scale (modified for lifting) | Reactive Training Systems (RTS) |
| Half steps | Yes (RPE 7.5, 8.5, etc.) | Usually whole numbers |
| Relationship | RPE = 10 - RIR | RIR = 10 - RPE |
RPE / RIR Conversion Table
| RPE | RIR | Meaning |
|---|---|---|
| 10 | 0 | Maximum effort - could not do another rep |
| 9.5 | 0-1 | Could maybe squeeze out one more |
| 9 | 1 | One rep clearly left in reserve |
| 8.5 | 1-2 | Between one and two reps left |
| 8 | 2 | Two reps clearly left in reserve |
| 7.5 | 2-3 | Between two and three reps left |
| 7 | 3 | Three reps left - moderate effort |
| 6 | 4 | Four or more reps left - easy |
RPE / RIR Converter
Enter an RPE or RIR value to instantly see the equivalent on the other scale.
= RIR
= RPE
Verdict
RPE and RIR are two sides of the same coin - RPE = 10 minus RIR. Neither is objectively better. Powerlifters typically use RPE; hypertrophy-focused lifters often prefer RIR. The most important thing is picking one system and using it consistently so your ratings become more accurate over time.
The RPE Scale for Powerlifting
The powerlifting RPE scale was adapted from Gunnar Borg's original effort scale by Mike Tuchscherer of Reactive Training Systems. While Borg's original scale ran from 6-20, the powerlifting version uses 1-10 with half-steps, where 10 represents a true maximum single and 6 represents an easy effort with four or more reps left.
The critical insight Tuchscherer added was mapping each RPE value to a percentage of 1RM at different rep counts. This created the Tuchscherer RPE Chart, which allows lifters to look up "if I'm doing 3 reps at RPE 8, that represents roughly 85% of my 1RM." This percentage table is the foundation of modern RPE-based programming.
Most serious powerlifting programs written since 2015 use RPE notation. If you see "3x3 @ RPE 8" in a program, that means three sets of three reps where each set ends with approximately two reps still available.
The RIR System Explained
Reps in Reserve (RIR) is conceptually simpler than RPE: you count how many more reps you could have done after finishing your set. A set ending with RIR 2 means you could have done two more reps before reaching failure. RIR 0 means you could not do another rep - absolute failure.
Research by Eric Helms and others has explored RIR as a practical autoregulation tool, particularly in hypertrophy training contexts. Studies suggest lifters tend to underestimate RIR (think they have fewer reps left than they actually do), especially when fatigued. This means programming targets like "keep RIR at 2-3" encourage leaving more reps in reserve than lifters typically would on their own.
RIR has gained significant traction in evidence-based hypertrophy communities and is frequently used in programs like those from Renaissance Periodization (RP). Many coaches prefer it for beginners because "leave 2 reps in reserve" is a more concrete instruction than "rate your exertion as 8 out of 10."
Converting Between RPE and RIR
The conversion between RPE and RIR is straightforward: RIR = 10 - RPE, and RPE = 10 - RIR. An RPE 8 set equals RIR 2. An RPE 9 set equals RIR 1. This simple relationship means you can follow any RPE or RIR program with either scale as long as you keep the conversion in mind.
The conversion becomes slightly less clean at RPE 9.5 (between 0 and 1 rep left) and for very light efforts below RPE 6. In practice, most programming stays in the RPE 7-9 range (RIR 1-3), where the conversion is clean and both systems agree perfectly.
Use the conversion tool above to translate between the two scales at any value.
Frequently Asked Questions
Calculations are for educational purposes. Individual results vary. Always consult your federation rulebook for official scoring and equipment rules.