One Rep Max Calculator

A one-rep max (1RM) is the maximum amount of weight you can lift for a single repetition of an exercise with proper form. It is used to measure strength and prescribe training loads.

Direct 1RM testing carries a higher injury risk and requires a spotter. Estimated 1RM via submaximal testing (using 3-10 reps) is safer and reasonably accurate for most lifters.

The Epley formula is most accurate for 2-10 repetitions. Accuracy decreases as rep count increases. For highly trained individuals, other formulas like Brzycki or Lander may give slightly different results.

Training programs typically prescribe percentages of 1RM. Strength training uses 85-95%, hypertrophy (muscle growth) uses 67-85%, and muscular endurance uses below 67%. This calculator provides the weights for each percentage.

Most strength coaches recommend testing or estimating 1RM every 4-12 weeks, coinciding with the end of a training block. More frequent testing may interfere with training progress.

Yes. Every exercise has its own 1RM. Deadlift 1RM is typically higher than squat 1RM, which is higher than bench press 1RM for most people. Always calculate separately for each exercise.