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One Rep Max (1RM) Calculator
Estimate your one-rep max from any lift using four science-backed formulas.
How it works
The one-rep max (1RM) is the maximum weight you can lift for a single repetition. These formulas estimate your 1RM from a submaximal lift — safer than actually attempting a true max. The Epley formula is the most widely used: 1RM = weight × (1 + reps/30).