Epley formula
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kg
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One Rep Max (1RM) Calculator
Estimate your one-rep max —the maximum weight you can lift for a single rep —from any weight and reps. Essential for designing strength training programs.
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Estimated 1RM (Epley formula)
Brzycki formula
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kg
How 1RM is estimated
Epley: weight×(1+reps/30). Brzycki: weight×36/(37−reps). Both validated for 3-10 rep sub-maximal lifts. Most reliable with 5RM or 10RM choices. Very high reps (>15) produce unreliable predictions.
Frequently asked questions
How accurate are the results?
Formulas used here are validated in population studies but cannot account for individual genetics, body composition, or medical conditions. Treat results as a starting point, not a medical diagnosis.
Should I consult a professional?
If you have specific health concerns, existing conditions, or are planning significant lifestyle changes, consult a qualified healthcare provider (doctor, dietitian, physiologist).
How often should I recalculate?
Recalculate when your weight changes more than 5%, activity level shifts significantly, or every 3-6 months for routine monitoring. Results are snapshots — your body changes daily.
Last updated
For general wellness information only, not medical advice — see our disclaimer.