Health Tool

One Rep Max Calculator

Estimate your one-rep max (1RM) for any lift based on weight and reps. Essential for powerlifting, bodybuilding, and strength training.

One Rep Max Calculator

Estimate your one-rep max (1RM) and see percentage breakdowns for your training cycles.

Weight Lifted

Repetitions

Estimated 1RM

113

Using Brzycki Formula

Training Percentages

100%113

95%107

90%101

85%96

80%90

75%84

70%79

65%73

60%68

50%56

How 1RM is calculated

A One Rep Max (1RM) is the maximum amount of weight you can lift for a single repetition of a given exercise. Since testing your absolute maximum can be dangerous and taxing, we use predictive formulas.

Our calculator uses the Brzycki Formula, developed by Matt Brzycki:
Weight / (1.0278 - (0.0278 * Reps))

Using training percentages

Most strength programs (like 5/3/1 or Starting Strength) rely on percentages of your 1RM rather than the max itself.

90-100%: Absolute strength and power development.
75-85%: Ideal for hypertrophy (muscle building) and strength.
60-70%: Muscular endurance and technique work.

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