One Rep Max Calculator
Enter a recent working set to estimate your one rep max and training percentages.
Fill in the form and hit calculate to see your results here.
Your estimated one rep max
Training percentages
Estimates get less reliable above about 10 reps — for best accuracy, use a set of 1-6 reps.
Why estimate instead of testing?
Testing a true 1RM is fatiguing and carries injury risk, especially for beginners. Estimating from a submaximal set gets you a useful number without the wear and tear.
Epley vs. Brzycki
Both formulas estimate 1RM from reps and weight, but weight the relationship slightly differently — we average them for a more balanced estimate.
Using the percentage table
Programs are often written as a percentage of 1RM — knowing your estimated max lets you calculate working weights for any prescribed intensity.
The formulas
# Epley 1RM = weight × (1 + reps / 30) # Brzycki 1RM = weight × 36 / (37 - reps) # We show Displayed 1RM = average of both formulas
Common questions
It's generally within a few percent of your true max for sets of 1-6 reps. Accuracy drops the higher your rep count goes, since fatigue starts to affect the relationship.
No — use the percentage table below to work out training weights at whatever intensity your program calls for, rather than testing the estimated max directly.
It works best for compound barbell lifts like squat, bench and deadlift. It's less reliable for isolation exercises or bodyweight movements.
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