FREE · SPORTS & TRAINING
One-Rep Max Calculator (1RM).
Estimate your one-rep max from any set using seven formulas, and get training loads from 50 to 100 % rounded to your plates.
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How to use One-Rep Max Calculator (1RM)
Enter the weight and the reps you completed, the unit and the smallest plate jump. The table gives loads by percentage with typical reps.
How it works
Averages Epley, Brzycki, Lombardi, O’Conner, Mayhew, Wathan and Lander. Reps per percentage use the Brzycki relation.
Example
100 kg for 5 reps estimates a 115.5 kg 1RM (Epley 116.7, Brzycki 112.5); 80 % is 92.5 kg.
Questions about One-Rep Max Calculator (1RM)
Is One-Rep Max Calculator (1RM) free, and do I need an account?
Yes. This tool is free to use in your browser without an account. Processing takes place on your device.
What are the limits and what should I check?
Best with sets of 3–8 reps taken close to failure. Everything is calculated in your browser; nothing you type is uploaded. Review the result before using it in your work.
Is my input sent to a server?
Your input is processed in your browser and is not uploaded by this tool. Files and pasted text are cleared when the page is refreshed. Normal website requests are still required to load the page and its libraries. Read the privacy explanation.