1RM calculator (one-rep max)

Estimate your one-rep max (1RM) from a submaximal set.

Weight lifted (kg)80kg

20–350 kg

Reps5

1–15

Result

93.3 kg

Your 1RM (one-rep max) is the most weight you can lift once on an exercise. Estimating it helps you plan training loads without testing a true max.

We use the Epley formula: weight × (1 + reps ÷ 30). It works best for sets up to about 10 reps.

FAQ

Why know your 1RM?

Many programs prescribe loads as a percentage of 1RM (e.g. 75% for hypertrophy). Estimating it avoids testing a true max, which is risky.

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