Two equations, one measured set
For load w and repetitions r, Epley = w × (1 + r/30); Brzycki = w × 36/(37 − r). Inputs accept 1–10 whole repetitions. At one repetition, both results use the lifted load directly.
One-rep max and training percentages
One Rep Max Calculator: 1RM & Training Percentages
Enter a lifted load and repetitions to compare two 1RM estimates and a percentage table.
No account needed. Free tracking, from the first entry.
The method, in plain language.
Using the percentage table
Choose an equation for loads at 50, 60, 70, 75, 80, 85, 90, 95 and 100% of estimated 1RM. Estimates depend on exercise, technique and proximity to technical failure; the table is not a safe training prescription.
Methods & sourcesBrzycki original paper and equation validation
Find the right starting point.
One shared calculation engine, with a focus that fits your goal.
A few useful answers
Do I need to attempt a maximum lift?
No. Use a submaximal set near technical failure with consistent technique. An estimated maximum remains uncertain and does not require an actual maximum attempt.
Why do the formulas give different results?
Epley and Brzycki model the load–repetition relationship differently. Both are estimates; selecting one changes the percentage table, not the load you actually lifted.