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One Rep Max (1RM) Calculator

Calculate your one-repetition maximum using 7 scientific formulas — Epley, Brzycki, Lander, Lombardi, Mayhew, O'Conner and Wathan. Get a complete strength percentage training chart.

7 FormulasInstant
🏋️ Your Lift
kg
reps
⚠️ Most formulas are most accurate for 1–10 reps. Above 10 reps accuracy decreases significantly.
💡 For best results, use a weight where you reach failure between 3–8 reps. Never attempt true 1RM without a spotter.
📊 Results
Estimated 1RM (Average)
120 kg
Based on 100 kg × 5 reps
Formula Breakdown
Formula1RM EstimateNotes
Training Percentage Chart
% of 1RMWeightGoal

FAQs — 1RM Calculator