One Rep Max Calculator

Your one-rep max is the most you could lift for a single rep. Estimating it from a normal set lets you program your training without ever testing a risky true max.

Weight lifted (kg)Reps performed

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How it's calculated

We use the Epley and Brzycki formulas, which estimate your max from the weight and reps of a set you have actually done. The percentage table then shows working loads for different goals.

How to read your result

Estimates are most accurate under about five reps and drift higher with very high-rep sets. Use the percentages to guide your programming: heavier and fewer reps for strength, lighter and more for size.

Common questions

How accurate is an estimated 1RM?

Close enough to program with, especially from sets of two to five reps. Above ten reps it becomes a rough guide rather than a number.

How do I use the percentage table?

Should I ever test my real max?

Method: Epley and Brzycki one-rep-max formulas.