One Rep Max Calculator
Estimate your one-rep maximum (1RM) by entering a weight you can lift for multiple reps. Uses 6 formulas (Epley, Brzycki, Lombardi, Mayhew, O'Connor, Wathan) plus a training percentage table.
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Frequently Asked Questions
Why does my 1RM matter for training?
Your 1RM is the anchor for percentage-based programming (Wendler 5/3/1, nSuns, Texas Method). Working at 75–85% of 1RM builds strength; 60–70% builds hypertrophy. Without a 1RM benchmark, training intensity is guesswork.
Which 1RM formula is most accurate?
No single formula is universally best. Epley and Brzycki are most widely used. Epley slightly overestimates at high reps; Brzycki is more conservative. Averaging multiple formulas (as this calculator does) reduces individual formula bias and is more reliable.
Should I actually attempt my calculated maximum?
Not necessarily. True max singles carry injury risk and require significant recovery. Most coaches recommend using a calculated 1RM for programming and testing actual max only at competitions or after 6–12 months of consistent training.