One Rep Max Calculator
Estimate the heaviest weight you could lift for a single repetition without testing a true max. Enter a recent set and get your 1RM and training loads.
How it works
- 1
Enter the weight
In kg or lb — the result uses the same unit.
- 2
Enter the reps
Sets of 2 to 10 reps give the most reliable estimates.
- 3
Plan your training
See your estimated 1RM and loads from 60% to 95%.
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Frequently asked questions
The average of Epley and Brzycki, both shown individually as well.
Why estimate your 1RM
Testing a true one-rep max is tiring and carries a higher injury risk. Formulas such as Epley and Brzycki estimate it from a submaximal set, and the calculator averages both for a balanced result.
Most strength programs prescribe loads as a percentage of 1RM: around 85–95% for heavy strength work and 65–80% for hypertrophy. Estimates are less accurate above 10 reps, so use heavier sets when possible.