What Is One Rep Max (1RM)?
One Rep Max (1RM) is the maximum weight you can lift for exactly one complete, technically correct repetition of an exercise. It is the gold standard for measuring absolute strength and is used to calculate training loads across all rep ranges.
Epley Formula (Most Common)
1RM = Weight × (1 + Reps ÷ 30)
Example: 80 kg × 5 reps → 1RM = 80 × (1 + 5/30) = 80 × 1.167 = 93.3 kg
Example: 80 kg × 5 reps → 1RM = 80 × (1 + 5/30) = 80 × 1.167 = 93.3 kg
Training Percentages Guide
| % of 1RM | Reps | Training Goal |
|---|---|---|
| 90–100% | 1–3 | Maximum strength / competition |
| 75–90% | 4–6 | Strength development |
| 65–75% | 8–12 | Hypertrophy (muscle size) |
| 50–65% | 12–20 | Muscular endurance |
| 30–50% | 20+ | Warm-up / rehabilitation |
Safety tip: For beginners, estimate your 1RM using a sub-maximal test (e.g. 8–10 reps) and avoid direct 1RM testing without an experienced spotter present.