What Is 1RM? Three Ways to Estimate or Measure Max Strength
Your one-repetition maximum, or 1RM, is the heaviest load you can lift once with an agreed movement standard. A paused competition bench press and a touch-and-go gym bench press are different tests, even if the number on the bar is the same.
1RM is useful for setting training loads and comparing the same lift over time. It is not a complete score for technique, readiness, or health.
Three ways to get a 1RM number
Direct test. Work up to the heaviest successful single. A systematic review found that properly conducted 1RM tests generally have good test-retest reliability across exercises, ages, and training backgrounds. Reliability does not remove the need for suitable equipment, technique, and spotting. See the review of 1RM test reliability.
Rep-based estimate. Enter a recent weight and repetition count in the MaxRep 1RM calculator. MaxRep compares seven formulas because no single equation fits every exercise and lifter. A set of 100 kg for 5 reps produces 116.7 kg with Epley and about 112.6 kg with Brzycki. Treat the spread as a reference range, not a measurement error that needs to be hidden.
Load-velocity estimate. Measure bar speed at several loads, fit your load-velocity relationship, and extrapolate toward a heavy single. This uses your own movement data, but the method still depends on exercise, device, load selection, and model. Reviews report useful monitoring potential alongside meaningful prediction uncertainty. Read the systematic review of load-velocity 1RM prediction.
Which input gives a better formula estimate
Use a technically consistent set of roughly 3 to 10 repetitions. Record the exercise variation, range of motion, equipment, and whether the set was near failure. A 5-rep set stopped with three repetitions in reserve should not be treated as a true 5RM.
Higher-repetition sets usually introduce more individual variation. Fatigue, pacing, and local muscular endurance begin to influence the answer more strongly than maximal strength.
Turn the estimate into a training baseline
After calculating 1RM, use the RM calculator for working weights or the RPE-based 1RM calculator when the set was not taken to failure. Keep the same movement standard when you calculate again. A trend built from comparable sets matters more than a one-day peak.
Power VBT adds another layer to that record. It analyzes a recorded or imported set, reports mean concentric velocity and bar path for each rep, and can build a load-velocity profile. Download Power VBT for iPhone or Power VBT for Android when you want to move from a formula estimate to your own lifting data.