One-Rep Max: Estimating Your Maximum Lift
Your one-repetition maximum (1RM) is the heaviest weight you can lift for exactly one complete rep with good form. Knowing your 1RM allows you to set precise training loads as percentages — rather than guessing what "heavy" means for any given exercise.
Key Formulas
Epley (most widely used):
1RM = weight × (1 + reps ÷ 30)Brzycki (more accurate at higher rep counts):
1RM = weight × 36 ÷ (37 − reps)Lombardi:
1RM = weight × reps⁰·¹Example: 100 kg for 5 reps
- Epley: 100 × (1 + 5/30) = 116.7 kg
- Brzycki: 100 × 36 ÷ 32 = 112.5 kg
Training Load Percentages
- 95% 1RM: 1–2 reps — maximal strength
- 85–90% 1RM: 3–5 reps — strength
- 70–85% 1RM: 6–12 reps — hypertrophy
- 50–70% 1RM: 12–20 reps — muscular endurance
- Below 50% 1RM: 20+ reps — endurance / warm-up
Most strength programmes use 70–85% of 1RM for primary working sets. These formulas become less accurate above 10 reps — test with a weight you can lift 3–8 times for the best estimate.
Track your heart rate zones for cardio work: Free Heart Rate Zones Calculator