One Rep Max (1RM) Calculator
Health
Estimate the heaviest weight you can lift once based on a sub-maximal set.
Epley: weight × (1 + reps/30)
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Estimates that update live
4 calculators
Health
Estimate your dog or cat's human-age equivalent, check Army body fat standards, or plan strength training around your one-rep max. Results update as you type and never leave your browser.
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Why use these calculators
Estimates, honestly labeled
These tools give research-based estimates, not diagnoses. Each page explains what the number can and cannot tell you.
Standards where they exist
The Army body fat tool follows the published tape method, and pet age tools use modern veterinary curves instead of the old seven-year myth.
Nothing to sign up for
Enter measurements, read results, close the tab. No account, and nothing you type leaves your browser.
Frequently asked questions
No. They provide educational estimates based on published formulas. For anything affecting your health or training, confirm the numbers with a qualified professional.