Estimated 1RM Comparison Calculator
Compare all 5 major 1RM formulas (Epley, Brzycki, Lander, Lombardi, Mayhew) side-by-side
Input Parameters
Real-time calculation updates dynamically as you adjust inputs. Values remain strictly local on your device.
Consensus 1RM (Mean)Spread: ±3
119kg
Calculated from 6 reps with 100 kg
Epley (1985)
120kg
Brzycki (1993)
116kg
Lander (1985)
117kg
| Formula | Estimated 1RM | Scientific Publication | Historical Context |
|---|---|---|---|
| Epley | 120 | Boyd Epley (1985) | Standard for collegiate football & power athletes |
| Brzycki | 116 | Matt Brzycki (1993) | Widely used linear fatigue slope equation |
| Lander | 117 | Jim Lander (1985) | Curvilinear velocity drop-off model |
| Lombardi | 120 | V. P. Lombardi (1989) | Exponential power factor formula |
| Mayhew et al. | 121 | Mayhew et al. (1992) | Derived from collegiate resistance training cohort |
Clinical Responsibility Note: Formulas show greatest agreement between 2 and 6 repetitions. As reps exceed 10, cardiovascular fatigue causes diverging estimations.
Mathematical Formula & Scientific Methodology
Formula: Comparative 1RM Matrix
Consensus = Average(Epley, Brzycki, Lander, Lombardi, Mayhew)Aggregates the five most peer-reviewed submaximal 1RM prediction models.
Model Assumptions
- Genuine technical failure
Variables & Standard Units
| Symbol | Physiological Meaning | Unit |
|---|---|---|
| Weight | Resistance lifted for multiple repetitions | kg/lb |
| Reps | Repetitions performed to momentary muscular failure | reps |
Scientific Limitations
- Higher reps (>10) increase estimation variance
Peer-Reviewed Scientific Citations
Poundage chart. Boyd Epley Workout (1985)
Epley B (1985) — University of Nebraska-Lincoln Strength Training Manual
Key Finding: 1RM = weight * (1 + reps / 30). Highly accurate for resistance exercises within 1 to 10 repetitions.
Frequently Asked Questions
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