1RM calculator and percentage loads
What you would lift once, worked out from the reps you actually do. Plus the percentage table to build the session.
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This is worked out here, in your browser. Nothing you type — weight, height, anything — leaves your phone: this page sends no data anywhere.
How it is worked out
Both classic formulas are used and the average is shown, because they disagree and hiding that would be faking precision. Epley: 1RM = weight × (1 + reps ÷ 30). Brzycki: 1RM = weight × 36 ÷ (37 − reps). With 5 reps at 100 kg, Epley says 117 kg and Brzycki 113. Below, the table splits that 1RM into percentages with the reps each one usually allows.
What it does not tell you
Both formulas were built on sets under 10 reps: above that the number runs away and stops meaning anything. And they depend on your endurance: two people with the same true 1RM can do 5 or 9 reps with the same weight. Use it to pick tomorrow's load, not to claim a number you have not lifted.
Where it comes from
Epley, B. (1985)
“Poundage Chart”, where the most used formula comes from.
Brzycki, M. (1993)
“Strength testing: predicting a one-rep max from reps to fatigue”, JOPERD.
LeSuer et al. (1997)
Comparison of prediction formulas in bench, squat and deadlift.
To read slowly
Free on Get NovastraThis is general training information, not medical or personalised nutrition advice. If you have a health condition, are pregnant or take medication, the person who decides is your doctor.