One Rep Max Calculator
Calculate your one-rep max and optimal training weights for any rep range based on strength training formulas.
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What is 1RM?
Your One Rep Max (1RM) is the maximum weight you can lift for a single repetition. It's the gold standard for measuring strength and planning training programs.
Training Percentages
Use your 1RM to calculate optimal training weights: 85-100% for maximal strength (1-5 reps), 67-85% for muscle growth (6-12 reps), and 50-67% for endurance (12+ reps).
Formula Accuracy
Different formulas work better for different rep ranges. Epley is most popular for 1-10 reps, while Brzycki tends to be more conservative and accurate for higher reps.
Disclaimer: This calculator provides estimates based on established formulas. Always use proper form and have a spotter when testing heavy weights. Consult a fitness professional before starting new training programs.