Estimate your 1RM and training percentages for bench, squat, deadlift, and strength programming.
This tool provides estimates for informational purposes only. It is not a substitute for medical, nutrition, or fitness advice. Individual results vary based on your health status, training background, body composition, and personal circumstances. Always consult a qualified healthcare or fitness professional before making important decisions based on the output.
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Your one-rep max (1RM) is the heaviest weight you can lift for a single repetition with good form. Testing it directly is demanding and carries injury risk, so this calculator estimates it from a set you can already complete. Enter the weight and the number of clean reps, and it applies established formulas such as Epley (1RM = weight × (1 + reps ÷ 30)) and Brzycki.
Estimates are most accurate when based on sets of 1–10 reps. The further you go beyond about 10 reps, the more the prediction drifts, because endurance and technique start to influence the result more than raw strength. For the best estimate, use a weight you can lift for 3–6 solid reps.
Knowing your 1RM lets you train with the right intensity without maxing out every session. Most strength programs prescribe loads as a percentage of 1RM: roughly 85–100% for maximal strength (1–5 reps), 67–85% for muscle growth (6–12 reps), and under 67% for muscular endurance (12+ reps).
Recalculate periodically as you get stronger so your working weights keep pace with your progress. Always warm up thoroughly with lighter sets, prioritise technique over numbers, and use a spotter for heavy barbell lifts. Treat the estimate as a planning guide, not a personal record to chase on every visit to the gym.
The calculator estimates 1RM from a submaximal set using proven formulas such as Epley (weight × (1 + reps/30)) and Brzycki. Enter the weight you lifted and how many clean reps you completed.
Estimates are most accurate at 1-10 reps and drift higher with very high rep sets. Using a weight you can lift for 3-6 reps gives the most reliable prediction.
Most strength programs prescribe training loads as a percentage of 1RM (for example 5 reps at 80%). Knowing your 1RM lets you set the right working weights without maxing out every session.
A true max attempt carries injury risk and needs a thorough warm-up, good technique and ideally a spotter. Estimating from a submaximal set is safer for most lifters.