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One-rep max calculator

The weight you lifted and how many times in, an estimated one-rep max by two formulas and a table from 50 to 95 percent out.

Your numbers

In any unit; the results come back in the same one. The default is an example.

Whole repetitions completed with good form. The default is an example.

Result

Estimated one-rep max (mean of the two)

114.6

Put a second set of numbers beside this one and see the difference.

Epley
116.7
Brzycki
112.5
95 % of your one-rep max
108.9
90 % of your one-rep max
103.1
85 % of your one-rep max
97.4
80 % of your one-rep max
91.7
75 % of your one-rep max
85.9
70 % of your one-rep max
80.2
65 % of your one-rep max
74.5
60 % of your one-rep max
68.8
55 % of your one-rep max
63
50 % of your one-rep max
57.3

100 for 5 repetitions gives an estimated one-rep max of 114.6: 116.7 by Epley and 112.5 by Brzycki.

Epley and Brzycki are estimates fitted to sets of a few repetitions; they get less reliable past about ten, and they are not a substitute for testing a true max with a spotter. The percentage table is taken from the mean of the two. One repetition is taken as the max itself.

The calculator estimates the heaviest weight you could lift once from a lighter weight lifted several times. Epley gives the weight times 1 plus the repetitions over 30; Brzycki gives 36 times the weight over 37 minus the repetitions. The table below the result takes percentages of the mean of the two.

Example. 100 for 10 repetitions is 133.3 by both formulas, the one count where they agree. 100 for 6 is 120 by Epley and 116.1 by Brzycki. One repetition is taken as the max itself.

Both are estimates fitted to sets of a few repetitions and get less reliable past about ten. The formulas are on their own pages: Epley and Brzycki.

Last reviewed October 20, 2026 ·How pages are reviewed

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