1RM Calculator (one-rep max)
Estimate your one-rep max and the percentage table to prescribe workouts safely.
How to use 1RM in programming
With your estimated 1RM you set set intensity: loads around 85-95% for strength, 67-85% for hypertrophy and up to 67% for endurance. Testing a true 1RM carries injury risk — estimating from a submaximal set is safer day to day.
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Frequently asked questions
What is 1RM?
1RM (one-rep max) is the heaviest load you can lift for a single repetition of an exercise. It is the reference used to set training intensity in percentages.
How is 1RM estimated?
This calculator uses the Epley formula: 1RM = weight × (1 + reps ÷ 30). It is an estimate from a submaximal set, without the risk of testing your true max load.
What is the percentage table for?
Workouts are prescribed as percentages of 1RM (e.g., 80% for strength, 70% for hypertrophy). The table shows the load matching each percentage so you can build your sets.
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