One Rep Max Calculator
Enter your lift weight and reps to estimate your maximum strength using scientifically-backed formulas.
Frequently asked questions
A one rep max (1RM) is the maximum amount of weight you can lift for a single repetition with proper form. It's used to measure strength, set training loads, and track progress over time.
1RM calculators are most accurate when using 1-10 reps. Accuracy decreases with higher rep ranges. The estimates are typically within 5-10% of actual 1RM for trained individuals using proper form.
For general training, Epley or Brzycki are good choices. For low reps (1-6), try Lombardi. For higher reps (8-15), Mayhew works well. Using the average of all formulas gives the most reliable estimate.
Testing actual 1RM carries injury risk and requires proper preparation. Estimated 1RM is sufficient for training programming. Only test actual 1RM if competing in powerlifting or when specifically required.