One Rep Max Calculator
Estimate one-rep max from lifted weight and repetitions.
This page is an editable estimator with realistic defaults so you can model your own situation in minutes.
Epley estimate: one-rep max = weight x (1 + reps / 30).
Treat the result as a planning estimate and verify important numbers with the relevant official source before acting.
| Primary equation | Epley |
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Assumptions
- One-rep max estimates are less reliable at high rep counts.
- Use proper spotting and coaching for max-effort lifting.
How this calculator works
Formula used
Epley estimate: one-rep max = weight x (1 + reps / 30).
Example calculation
Plug in your own numbers and the result updates instantly. Epley estimate: one-rep max = weight x (1 + reps / 30).
One Rep Max Calculator FAQ
Is this one rep max calculator medical advice?
No. It is an educational estimate only and should not be used to diagnose, treat, or make medical, nutrition, legal, or emergency decisions.
Why might my real result be different?
Age, sex, body composition, pregnancy, medications, medical conditions, training status, lab methods, and measurement accuracy can all change real-world results.
Should I check these results with a professional?
Yes. Confirm health, nutrition, fitness, kidney function, alcohol, or safety decisions with a qualified professional or official source.