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RPE & RIR Calculator

Enter one recent set and its RPE. The calculator builds a personal RPE chart — an approximate load for every rep target and effort level — as a starting point you adjust on the day.

Calculator

Your recent set

Unit

Estimated 1RM (approximate)

122.5 kg

Your set: about 82% of that max.

Next set: starting point

reps at RPE

≈ 110 kg

Adjust after the first set if it feels easier or harder than intended.

Your RPE chart

Approximate loads by reps (rows) and RPE (columns)
Reps109.598.587.576.56
1122.5117.5115115112.5110110107.5105
2115115112.5110110107.5105105102.5
3112.5110110107.5105105102.5102.5100
4110107.5105105102.5102.510097.597.5
5105105102.5102.510097.597.59595
6102.5102.510097.597.5959592.592.5
710097.597.5959592.592.59087.5
897.5959592.592.59087.587.585
1092.59087.587.585····

Columns are RPE (10 = no reps left). Loads are rounded to 2.5 kg; “·” marks combinations more than 12 reps from failure. Your set is highlighted.

Runs in your browser; nothing you enter is stored on our servers or sent anywhere.

How the chart is built

RPE (rating of perceived exertion) in strength training is anchored to reps in reserve: RPE 10 means no more reps were possible, RPE 9 one more, RPE 8 two, with half points for uncertainty [1] [2]. A set of 5 at RPE 8 was therefore about 7 reps from failure.

The calculator converts your set into an estimated one-rep max with the average of the Brzycki and Epley equations — the same method as our one-rep max calculator — then works backwards to every combination of reps and RPE. It is an equation-based chart built from your own numbers, not a fixed table from a coaching system.

What the evidence says about effort ratings

The RIR-based RPE scale was validated in experienced and novice squatters: ratings tracked bar speed closely, so the scale reflects real proximity to failure [1]. In an eight-week trial in trained men, choosing loads to hit target RPEs produced similar strength and muscle gains to fixed percentages of 1RM [3].

Estimates are imperfect, though. A meta-analysis of 12 studies found that people underestimate how many reps they have left by about one on average, with wide variation; predictions were more accurate closer to failure and in sets of 12 reps or fewer [4]. In the bench press, subjective estimates were least accurate in early sets and with lighter loads [5].

Limitations

Use the chart as a starting point, then let the first work set tell you whether to adjust.

  • RPE and percentage of 1RM are not interchangeable: the same percentage can be RPE 7 one day and RPE 9 the next, depending on fatigue, sleep and technique.
  • Every number here is approximate: it inherits the error of the 1RM equations and of your own RPE rating.
  • The reps–load relationship varies between exercises and people [6] — the chart from a squat set is not your bench press chart.

Using RPE in your training

Most heavy compound work sits at RPE 7–9 and hypertrophy accessories at RPE 8–10. Our guide to RPE and RIR covers how to calibrate your ratings, and how close to failure to train explains why the effort level matters more for muscle growth than for strength.

Frequently asked questions

What does RPE 8 mean in lifting?

You stopped with about two good reps left. On the reps-in-reserve scale, RPE 10 means no reps left, RPE 9 one, RPE 8 two and RPE 7 three [2].

Is RPE more accurate than percentages?

Neither is exact. Percentages ignore day-to-day readiness; RPE depends on how well you judge effort, and most people misjudge it by about a rep [4]. Many lifters combine them: a percentage to start, RPE to adjust.

Sources

  1. [1]Zourdos MC, Klemp A, Dolan C, et al. Novel Resistance Training-Specific Rating of Perceived Exertion Scale Measuring Repetitions in Reserve. Journal of Strength and Conditioning Research. 2016;30(1):267–275. Source
  2. [2]Helms ER, Cronin J, Storey A, Zourdos MC. Application of the repetitions in reserve-based rating of perceived exertion scale for resistance training. Strength and Conditioning Journal. 2016;38(4):42–49. Source
  3. [3]Helms ER, Byrnes RK, Cooke DM, et al. RPE vs. percentage 1RM loading in periodized programs matched for sets and repetitions. Frontiers in Physiology. 2018;9:247. Source
  4. [4]Halperin I, Malleron T, Har-Nir I, et al. Accuracy in predicting repetitions to task failure in resistance exercise: a scoping review and exploratory meta-analysis. Sports Medicine. 2022;52(2):377–390. Source
  5. [5]Hickmott LM, Butcher SJ, Chilibeck PD. A comparison of subjective estimations and objective velocities at quantifying proximity to failure for the bench press in resistance-trained men and women. Journal of Strength and Conditioning Research. 2024;38(7):1206–1212. Source
  6. [6]Shimano T, Kraemer WJ, Spiering BA, et al. Relationship between the number of repetitions and selected percentages of one repetition maximum in free weight exercises in trained and untrained men. Journal of Strength and Conditioning Research. 2006;20(4):819–823. Source

Keep going

Related guides

How to rate effort accurately, and how much effort each training goal needs.

Training Fundamentals

RPE and RIR Explained: How to Measure Effort in the Gym

What RPE and reps in reserve mean, how accurate lifters are at estimating them, and how to use effort ratings to set loads and manage fatigue.

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Hypertrophy

Training to Failure: How Close Should You Go?

Whether you need to train to failure for muscle growth and strength, what reps in reserve means, and how to set effort on different exercises.

7 references · 5 minRead

Strength

How to Get Stronger: An Evidence-Based Guide to Strength Training

The principles that drive strength gains — heavy loads, specific practice, frequency, volume and periodisation — and how to build them into a programme.

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