Health & Fitness
One Rep Max Calculator - 1RM
Estimate your one rep max and training max from a working set.
Formulas and edge cases are reviewed against authoritative references before publication. For methodology, editorial standards, or corrections, use the links below.
Frequently asked questions
Which formula is used?
This calculator uses the Epley formula for estimating 1RM.
How many reps should I use?
Best results are usually with 3-10 reps.
What is training max?
Training max is 90% of estimated 1RM, often used for programming.
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About this tool
This One Rep Max Calculator turns your inputs into practical results. Provide Weight lifted and Reps to calculate Estimated 1RM and Training max (90%).
Adjust values to compare scenarios and see how sensitive the result is. The calculation uses the numbers as entered, so double-check units and expect small differences from rounding in the displayed totals.