One-rep max calculator.
Estimate your 1RM from any set, without testing a true max. This uses the same formulas as Ritual Lab: the average of Epley and Brzycki.
Free calculator
Estimates for general guidance, not medical advice. See the medical disclaimer and sources.
How it works
The formula.
Epley estimates weight × (1 + reps ÷ 30). Brzycki estimates weight × 36 ÷ (37 − reps). Ritual averages the two.
Questions
Frequently asked
How is one-rep max calculated?
This calculator averages the Epley and Brzycki formulas, using the weight and reps from a set.
How many reps give the best estimate?
Sets of fewer reps taken close to failure generally give a closer estimate than very long sets.
Can I track my 1RM over time?
Yes. One-rep max is free forever in Ritual, which saves your results and charts each lift.
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