One Rep Max Calculator
Your one rep max (1RM) is the most you could lift once. Enter a recent set of 1 to 12 reps to estimate it, plus the weights for common training percentages.
How we got it
The average of the Epley (weight x (1 + reps / 30)) and Brzycki (weight x 36 / (37 - reps)) formulas. Shown as plus or minus 3% for 1 to 3 reps, 5% for 4 to 6, and 10% for 7 to 12, because estimates get looser as reps rise.
Updated . Sources: Epley, 1985, Boyd Epley Workout; Brzycki, 1993, Journal of Physical Education, Recreation and Dance.
Questions
Is it safe to test a true 1RM?
Estimating from a set of 3 to 8 reps is safer and close enough for planning. If you test, warm up well and use a spotter or safety bars.
Does it work for bench press, squat and deadlift?
Yes, the same formulas are used for all main barbell lifts.