How to Use This Calculator
Enter the weight you lifted and the number of clean reps you completed in a recent set, taken close to failure, and your estimated one-rep max updates instantly across three formulas, alongside a full percentage-based training chart. For the full explanation of how these formulas were derived, which one tends to be most accurate at different rep ranges, and a worked example for every calculation on this page, see the "How to Use the 1RM Calculator" section of our complete guide.
Read the full guide first for the best context: how the Epley, Brzycki, and Lombardi formulas were derived, which is most accurate at which rep range, how to actually use a percentage chart to structure training, and a detailed worked example for every calculation on this page are all covered in our 1RM Calculator Guide 2026 →
This calculator provides general estimates for informational and educational purposes only. It is not medical or professional coaching advice. Estimated 1RM formulas are approximations based on population averages and can vary from your true one-rep max. Never attempt a true 1-rep max lift without a spotter, safety bars, or a qualified professional present, and consult a doctor before beginning any new strength training program.