One Rep Max Calculator
Estimate your one-rep max (1RM) — the maximum weight you can lift for a single repetition — without attempting a risky max lift. Enter a weight and the reps you can perform with it, and see your estimated 1RM plus training percentages.
One Rep Max Calculator
fitness calculator
How It Works
Formula
Epley Formula: 1RM = weight × (1 + reps / 30)
Examples
100 kg for 5 reps
Estimated 1RM of about 117 kg.
Frequently Asked Questions
What is a one rep max?
Your one-rep max (1RM) is the most weight you can lift for one full repetition of an exercise. It is the standard measure of strength and is used to set training intensities.
How accurate is the 1RM estimate?
Estimates are most accurate in the 1-10 rep range. Above 10 reps, accuracy drops because endurance becomes a bigger factor than pure strength.
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