Body Metrics Calc is a small set of free calculators for adults in the United States: a body fat calculator (US Navy, Army and BMI methods), a lean body mass calculator, a one-rep max calculator and a bench press calculator. You enter a few measurements, and the page returns an estimate with the formula behind it.
The site is run by AUSSIE-AI LTD, a small company based in the UK. There is no team of doctors, trainers or sports scientists behind it, and we do not claim any. The pages are written from published sources, and each one lists them at the bottom.
Where the formulas come from
We use published equations and name the source on each page: the Navy and Department of Defense equations from reports by the Naval Health Research Center, the Army equations from Army directives, the BMI-based equation from a 1991 journal paper, and the lean mass and one-rep max formulas from the research and training literature. Where we could not read an original paper, we say which secondary source we used. Where sources disagree, we show both.
Our test cases include worked examples, among them two published by the Army. The numbers on each page can be recalculated by hand from the formula shown.
What these calculators are not
They give estimates, not measurements. Every method here has an error of several percentage points or several percent of the load, and we say so on the pages.
They are not medical advice. Nothing here diagnoses, treats or screens for a condition, and no result means you should or should not change your health habits. If you have a health concern, see a qualified professional.
They are not a fitness or military assessment. If your employer, coach or service sets a standard, follow their official procedure. Rules for body composition in the US military have changed twice since 2023, so check the current policy.
We left out a few things on purpose. There is no bench press strength table by bodyweight, because we could not find a published source we trusted and could cite. There are no "ideal weight" outputs.
Advertising and independence
The site may show advertising, which is how it is paid for. We do not take payments from any brand, and we have no affiliation with any organization whose published data we cite.
Corrections
If you find a figure that looks wrong, tell us through the contact details on this site, and we will check it against its source.
Who runs the site
Body Metrics Calc is operated by AUSSIE-AI LTD, a company registered in England and Wales (company number 17193460). To report a figure or ask a question, use the contact page or email hello@bodymetricscalc.com.