Estimate your 1RM from any set using 7 scientific formulas. Get training percentages for strength, hypertrophy, power, and endurance zones — without maxing out.
💡 Epley and Brzycki are the most commonly used. Average of all 7 gives the most balanced estimate.
Training Zones
Based on your estimated 1RM — use these weights in your programming:
Rep Max Table
Predicted max weight for each rep range:
Reps
% of 1RM
Weight (kg)
Training Zone
What Is a One Rep Max?
Also searched as: one rep max calculator free | 1rm calculator | max bench calculator | powerlifting max calculator Optimized for US users with American units and terminology.
Your one rep max (1RM) is the maximum weight you can lift for a single repetition with good form. It's the universal benchmark for strength in powerlifting and strength training. Rather than actually performing a maximal lift (which carries injury risk), you can estimate your 1RM by lifting a submaximal weight for multiple reps and using one of several validated formulas.
Which 1RM Formula Is Most Accurate?
All formulas become less accurate as rep count increases beyond 5–6. For sets of 1–6 reps, most formulas agree within 2–3%. The Epley and Brzycki formulas are the most widely used and generally considered most reliable. The average of multiple formulas reduces the impact of individual formula errors. Never attempt a true max without an experienced spotter.
Use the One Rep Max Calculator above — enter your values and get instant results. This free online tool calculates how to calculate one rep max without any download or signup required. Results update in real time as you type.
Use the One Rep Max Calculator above — enter your values and get instant results. This free online tool calculates 1 rep max bench press calculator without any download or signup required. Results update in real time as you type.
Rarely. Training at 100% 1RM is for competitive testing, not for regular training. For strength, train at 80–90% 1RM for 1–5 reps. For hypertrophy (muscle growth), 65–80% for 6–12 reps is optimal. For endurance and conditioning, 50–65% for 12–20+ reps. Regularly training above 90% increases injury risk significantly.
Most strength coaches recommend testing true 1RM only at the end of a training cycle — every 8–16 weeks. Frequent 1RM testing is taxing on the CNS and joints, and takes time away from productive training. Instead, test a 3RM or 5RM regularly and use this calculator to estimate your current 1RM.