aifithub
Strength As of 2026-04-24

How RPE to Percentage Converter works

Methodology for the RPE to Percentage Converter: formulas, coefficients, data sources, assumptions, and known limitations.

Scope

Converts RPE and reps to a percentage of 1RM using the Tuchscherer RPE chart.

Formula

pct_1rm = table(rpe, reps) from Tuchscherer's published RPE chart.

Coefficients

Parameter Value Note
Chart row count RPE 6 to 10 in 0.5 steps
Chart column count Reps 1 to 12

Data sources

  1. Zourdos MC, Klemp A, Dolan C, et al. Novel resistance training-specific rating of perceived exertion scale measuring repetitions in reserve. J Strength Cond Res. 2016;30(1):267-275. — PMID 26049792. Peer-reviewed RIR-based RPE chart covering the same cells as Tuchscherer's original table.
  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 Cond J. 2016;38(4):42-49. — Practical-application companion paper.
  3. Tuchscherer M. The Reactive Training Manual. Reactive Training Systems, 2008. — Original coaching manual; self-published and not peer-reviewed.

Assumptions

  • User can reliably self-report RIR; novices over-estimate reserve by 2–3 reps.

Approximation range

Chart accuracy within ~3% of 1RM for experienced lifters on bench and squat.

Limitations

  • RPE drift on high-rep sets is substantial; prefer RPE for 1–6 rep sets.
  • RPE for deadlift and accessory lifts is less calibrated than for the competition lifts.

Reproducibility

RPE 8 x 5 reps ≈ 84% of 1RM (from Tuchscherer chart).

Change log

  • 2026-04-24: methodology page first published.
General fitness estimates — not medical advice. Consult a healthcare professional for medical decisions.