Strength Calculators
Estimate your one-rep max from any set and find the right weights for every training zone.
Methodology
1RM Estimator averages two formulas to estimate your one-rep max from a working set. Most reliable for 2–10 reps.
Training Loads takes your known 1RM and shows what weight to use at each percentage, with rep ranges for each zone.
Formulas
Epley (1985): 1RM = weight × (1 + reps / 30)
Brzycki (1993): 1RM = weight × 36 / (37 - reps), more accurate below 10 reps
The estimate averages both. Above 10 reps Brzycki loses accuracy, so treat higher-rep results as a rough guide.
Training Zones
| % 1RM | Reps | Goal |
|---|---|---|
| 90–95% | 1–3 | Maximal strength |
| 80–90% | 3–6 | Strength |
| 70–80% | 6–10 | Strength / hypertrophy |
| 60–70% | 10–15 | Hypertrophy |
| 50–60% | 15–20+ | Muscular endurance |
Sources: Epley (1985) Boyd Epley Workout; Brzycki, M. (1993). Strength Testing. JOPERD 64(1).
Note: Results are estimates based on population averages. Individual responses vary. Nothing here is medical advice. Talk to a doctor or coach before changing your training or nutrition.