About BodyStats

BodyStats exists because of a specific frustration: nearly every body-composition calculator on the internet gives you one number, checked against one threshold table from the 1990s, with no indication of how much uncertainty is baked into it or which population the thresholds were drawn from.

That is not a small omission. A BMI of 23 is "normal" under the WHO standard classification and "overweight, at risk" under the WHO Asia-Pacific classification, both published by the same organisation, both correct within their own system. A tape-based body fat estimate is genuinely useful and genuinely carries a ±3–4 percentage point error band. A TDEE figure presented as a clean integer is a population average wrapped around a ±10–15% range. Sites that hide these facts are not being simpler; they are being less true.

So this site shows the classification systems side by side, prints the error bands next to the results, cites a primary source for every formula and threshold on the methodology page, and refuses to compute calorie targets that fall below established safety floors; the guardrails are enforced in the calculation code itself, not just written in the copy around it.

What is on the site now

BodyStats publishes 43 calculators, 26 sourced guides explaining the reasoning behind the numbers, and 7 reference charts generated directly from the calculation engine rather than typed out by hand. Alongside them sit a glossary defining every term the site uses in one place, and a public changelog recording what changed, when and why, corrections included. The full list of calculators and guides, each with the date of its last substantive change, is on the author page.

The reference charts are:

• BMI chart by height and weight: The weight at every WHO boundary for your height, in kg, lb and stone, with the Asia-Pacific cut-offs alongside and the classic grid.
• Healthy weight chart by height: The healthy weight range for every adult height, plus what the four classic ideal-weight formulas say and why the range is the better answer.
• Body fat percentage chart by age and sex: Two recognised interpretation systems side by side: the ACE fitness categories and the age- and sex-specific healthy ranges from Gallagher et al.
• Daily calorie needs chart by age, sex and activity: Maintenance calories by age, sex, height, weight and activity level, with the ±10–15% band printed, and the official estimates alongside.
• Healthy waist size chart by height and sex: Half-your-height targets for every adult height, the WHO waist thresholds, and the ethnicity-specific values the IDF publishes.
• Walking Calorie Chart by Pace, Weight and 30 Minutes: Gross kilocalories for a 30-minute walk at five Compendium paces, for 60 to 100 kg. Same cardioSession maths as the walking calculator, as a lookup table.
• Alcohol Calorie Chart by Drink, Serving and Daily Budget: Typical drink calories for beer, wine, spirits and cider, as a share of a 2,000 and 2,500 kcal day. Same serving values as the alcohol calculator on this site.

Who publishes it

BodyStats is built and published by PineSeed Pty Ltd, an Australian software company, and written by Rick Campbell. We are software people, not clinicians, which is exactly why every page is anchored to published primary literature rather than to our opinions, and why the site is careful to mark the line where a calculator stops and a doctor starts.

How this site is built

Every number on the site comes out of one shared calculation engine: a single set of pure functions, with no interface code in them, used by the server and by your browser alike. That is why a result cannot differ between the page you are served and the page after it finishes loading, and why the reference charts are guaranteed to agree with the calculators; they are computed by the same functions rather than transcribed into a table.

Those functions are pinned by locked test vectors: expected values worked out by hand from the published formula, plus boundary cases and impossible inputs, held in an automated test suite. Any change that moves a published result fails the build before it can ship, so a correction stays corrected and a regression cannot slip out quietly.

The pages are rendered on the server and work without JavaScript. Every calculator form posts to its own address and returns a full result: the classification tables, the bands and the reference content are in the HTML before any script runs, so the site works on a slow connection, an old phone, a locked-down work machine or a text browser. JavaScript, where a page loads any at all, only adds live recalculation as you type.

How it makes money

The calculators are free and require no account. The site is intended to be supported by advertising, placed below results and never between an input and its answer, and never at all on pages showing a low-BMI or blocked-goal result. We do not and will not take affiliate money from supplements, diet pills or weight-loss programs.

What we do not do

We do not store your measurements against you; there is no account, no profile and no way to join a calculation back to a person. See the privacy page. We do not claim medical review that has not happened; see reviewers. And we do not use before-and-after imagery, "ideal body" framing, or language that applies a category to a person rather than to a number.