One-rep max (1RM) calculator

1RM is the heaviest weight you can lift once with proper form, estimated here with the Epley (w × (1 + reps ÷ 30)) and Brzycki (w × 36 ÷ (37 − reps)) formulas and their average. Most accurate from 2–10 reps. Never test a true max without a spotter and warm-up.