One Rep Max Calculator

Your One Rep Max (1RM) is the maximum weight you can lift for a single repetition. Since testing your true 1RM can be risky, these formulas estimate it based on submaximal lifts.

Best practices: Use a weight you can lift with good form for 3-8 reps. The estimates become less accurate above 10 reps. Always warm up properly and use a spotter when testing heavy lifts.

Training applications: Use the percentage chart to program your training. For example, working sets at 70-80% are great for hypertrophy, while 85-95% builds maximal strength.