How this RPE calculator estimates weight
RIR ≈ 10 − RPE. The planning estimate is e1RM = weight × (1 + (reps + RIR) / 30). Next-set load is e1RM / (1 + (target reps + target RIR) / 30), rounded down to your chosen total load increment. A maximal single (one rep at RPE 10) is treated as the observed max in both directions.
For 100 kg × 5 at RPE 8, RIR is about 2 and e1RM is about 123.3 kg. Targeting 5 reps at RPE 9 gives about 102.8 kg before rounding, or 102.5 kg with a 2.5 kg increment. This is a model output, not a promise that your next set will feel like RPE 9.
Use the same exercise, range of motion and technique for the completed and planned sets. RPE is subjective, half-points express uncertainty, and fatigue between sets is not modeled. This is not the RTS empirical chart or an individualized training prescription. Stop or reduce the load if technique or comfort deteriorates.
Compare the Epley formula and Brzycki formula, or send your result directly to the percentage calculator and warm-up planner using the buttons above.
Reproduce the example in kg or lb
- Use the completed-set example link above, or enter 100 kg, 5 reps and RPE 8. The link fills only the completed set; it does not set the target effort.
- Under Next set, choose 5 reps, RPE 9 and a 2.5 kg total load increment. This increment is for the whole bar, not each side.
- Check 2 reps in reserve, 123.3 kg estimated 1RM and a 102.5 kg next-set suggestion. The calculator keeps the unrounded estimate internally; it rounds down only the suggested load.
- To check the same completed set in pounds, change Unit to lb. The input becomes 220.46 lb and the increment resets to 5 lb. With the same reps and RPE targets, the estimate displays 271.9 lb; about 226.6 lb before rounding becomes a 225 lb suggestion.
The kg and lb suggestions need not be exact conversions: 2.5 kg and 5 lb are different increments, and the converted input is kept to two decimal places. Do not replace 100 kg with 100 lb when comparing the same physical load.
Continue from Your estimate: Percentage loads carries the estimated 1RM (123.3 kg displayed), while Plan warm-up sets carries the rounded next-set load (102.5 kg in the kg example). On the warm-up page, confirm the exercise, work weight, bar weight and available plates before using the plan. These existing result links use your current inputs, not fixed example values.
If a result is unavailable, use a positive weight and keep both completed reps + RIR and target reps + RIR at 12 or fewer. Correct the field or reload the completed-set example and set the target again. A valid model result still does not account for fatigue or guarantee that you can complete the next set.
RPE to reps-in-reserve table
RPE is useful because it adds a confidence range to percentage work. A planned 85% set can be a clean RPE 7 on a strong day or a slow RPE 9.5 when recovery is poor. The load decision should follow the set you actually performed.
Scroll table horizontally
| RPE | RIR | Meaning | Next load decision |
|---|---|---|---|
| 10 | 0 | True max effort | No reserve reps. Choose a lower target effort if more work is planned. |
| 9.5 | 0-1 | Maybe one clean rep left | Near the limit; account for fatigue before repeating. |
| 9 | 1 | Heavy top set | Use as a realistic daily strength marker. |
| 8 | 2 | Hard but repeatable | About two clean reps left; use your program’s target. |
| 7 | 3 | Moderate volume set | Compare with the planned RPE before changing load. |
| 6 | 4 | Technique or warm-up load | Keep for practice or enter the planned target above. |
| 5 or below | 5+ | Easy warm-up | Use only for ramping, recovery, or speed practice. |
Lift-specific RPE advice
RPE is not only a number. It depends on whether the movement still matched the standard you intended to train.
Scroll table horizontally
| Lift | RPE signal | Training advice |
|---|---|---|
| Bench press | Bar speed slows near lockout | Use 2.5-5 lb jumps and keep the same pause standard. |
| Squat | Depth or torso angle changes | Treat the set as higher RPE and hold or reduce the next jump. |
| Deadlift | Grip, breathing, or back position limits reps | Cap most work at RPE 8-9 and avoid repeated RPE 10 pulls. |
| Overhead press | Layback or knee dip appears | Count it as a different movement and use the lower load. |
How to use RPE with a 1RM estimate
Start with your estimated 1RM or training max, choose the planned percentage, then let RPE decide whether the load is believable today. If a set planned at RPE 8 feels like RPE 9.5, reduce the next set by 2.5-5%. If it feels like RPE 6, add a small jump or keep the load for cleaner volume.
The goal is not to turn every workout into a max test. RPE adds subjective effort context: the same 1RM can produce different useful training loads depending on fatigue, skill, and the lift standard that day.
Related calculators
- Printable RPE percentage and load chart
- Training Max Calculator
- 1RM Formula Comparison
- Warm-up Calculator
Sources
- Zourdos et al. 2016 - Novel resistance training-specific RPE scale measuring repetitions in reserve.
- Helms et al. 2016 - Application of the repetitions in reserve-based RPE scale for resistance training.
FAQ
Is RPE a calculator or a chart?
For strength training, RPE is a practical lookup from effort to reps in reserve. Use the table to adjust load after each set.
What is RPE 8?
RPE 8 usually means about two clean reps in reserve. It should feel hard but repeatable.
How much should I change the weight?
For barbell lifts, small jumps of 2.5-5% are usually enough. Larger jumps make sense only when the previous set was clearly too easy.