One-Rep Max (1RM) Calculator
Estimate your one-rep max from the weight and reps you lifted with the Epley, Brzycki and Lombardi formulas, plus a percentage chart for programming.
For general information only — not medical advice. Results are estimates; talk to a doctor or qualified health professional about your own health.
How to use
- 1Enter the weight you lifted and how many clean reps you did (ideally 2–10).
- 2Use the percentage table to plan training weights.
How it's calculated
Epley: 1RM = w × (1 + reps ÷ 30). Brzycki: w × 36 ÷ (37 − reps). Lombardi: w × reps^0.10. The average is shown as the estimate.
Frequently asked questions
How accurate are 1RM estimates?
Best with 2–10 reps. Beyond about 12 reps the formulas become unreliable because endurance plays a bigger role.
Should I test my true 1RM?
Only with good technique, a warm-up and a spotter or safety bars. Many lifters prefer estimates to avoid the risk.
What percentage should I train at?
Roughly 85%+ of 1RM for strength (1–5 reps), 67–85% for muscle growth (6–12 reps) and below 67% for endurance.