Free calculator

1RM Calculator: Find Your One-Rep Max

Enter the weight you lifted and how many full reps you completed (ideally 3 to 8). We estimate your max and the weight for each percentage.

Formulas we use

Epley: weight × (1 + reps ÷ 30). Brzycki: weight × 36 ÷ (37 − reps). We show the average of the two, which works well up to about 10 reps.

You'll find full guidelines on every exercise page, for example the barbell back squat.

Is it safe to test my true 1RM?

Only with good technique, a progressive warm-up and a spotter. For most people it's better to estimate it from a set of 3-5 reps.

Does it work for every exercise?

It's more reliable for the big lifts (squat, bench press, deadlift, overhead press) than for isolation exercises.

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