Estimate your 1RM and get personalized training zone weights using proven formulas.
Quick Answer:Enter the weight and reps you performed, and this calculator will estimate the maximum you can lift for a single rep using the Epley and Brzycki formulas.
Estimated One Rep Max
Calculating... lbs (average)
Epley Formula
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Brzycki Formula
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Strength Zone (90-100%)
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1-3 reps
Hypertrophy Zone (70-85%)
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4-8 reps
Endurance Zone (60-70%)
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8-12 reps
Exercise
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For the most accurate 1RM estimate, use a weight that you can lift for 3-5 reps with good form. The formulas become less reliable above 10 reps. Also remember that your 1RM varies by exercise -- a calculated squat 1RM is not interchangeable with your bench press 1RM. Always warm up thoroughly before attempting a true one-rep max, and ideally have a spotter present.
A one rep max (1RM) is the maximum amount of weight you can lift for a single repetition with proper form. It matters because it serves as a benchmark for programming training intensity. Most strength programs prescribe loads as a percentage of your 1RM, so knowing this number helps you select the right weight for each set and rep scheme.
The Epley and Brzycki formulas are most accurate when using rep counts between 1 and 10. Accuracy decreases significantly above 10 reps because higher-rep sets depend more on muscular endurance than pure strength. For best results, use a weight you can lift for 3-5 reps with good form.
Training zones divide your 1RM into percentage ranges that target different adaptations. The strength zone (90-100% of 1RM, 1-3 reps) builds maximal force production. The hypertrophy zone (70-85%, 4-8 reps) maximizes muscle growth. The endurance zone (60-70%, 8-12 reps) improves muscular endurance and work capacity.