How do I calculate one rep max? Enter your numbers above and the result updates instantly. For example: Weight lifted: 185 lb · Reps performed: 5 → Estimated 1RM (Epley): 216 lb.
Is this One Rep Max Calculator free? Yes — completely free with no sign-up or paywall. It runs entirely in your browser and keeps working offline; the numbers you enter never leave your device.
How accurate is it? It uses the standard published formula for one rep max. Results are estimates for planning — not financial, tax, medical, engineering, or legal advice.