Rick Campbell

Founder, PineSeed Pty Ltd · Author and developer, BodyStats

Rick Campbell is the founder of PineSeed Pty Ltd, an Australian software company. He builds BodyStats and writes what is on it: the calculators, the guides, the reference charts, and the trust pages you are reading now. There is no content team behind this site and no roster of freelance writers; 69 calculator and guide pages, plus the charts and reference material, are the work of one person, which is worth knowing before you decide how much weight to give any of it.

He is a software engineer, not a clinician, and does not present himself as one. That distinction is the most useful thing this page can tell you, so the rest of it sets out precisely what that expertise does cover, where it stops, how the pages are produced and checked, and what he will not do. Everything here is checkable: every formula is written out on the page that uses it, every threshold carries a primary source, and every published result is pinned by an automated test.

What this expertise actually covers

On a body-composition calculator site, most of the questions that decide whether a number can be trusted are engineering questions rather than clinical ones. The science was settled and published by other people, in papers and technical reports that anyone can read. What determines whether a site is honest about that science is whether the person implementing it is disciplined about five things:

• Implementing the published formula exactly. The coefficients as the original authors printed them, in the units they used, without silent rounding, without a "simplified" variant, and without quietly substituting a different equation because it was easier to code. Where a method has several published versions, the page says which one it computes.
• Citing the primary source. The paper, the technical report or the official publication the number came from, with a DOI or an official URL, shown on the page itself and gathered on the methodology and references pages. Never another calculator site, never a content farm, never a secondary summary standing in as authority for a figure.
• Printing the error band. A tape-based body fat estimate carries roughly ±3–4 percentage points. A total daily energy expenditure figure is a population average wrapped around a ±10–15% range. Those bands are published in the same literature as the formulas, and they belong next to the result, not in a footnote a visitor will never open.
• Enforcing the safety limits in code. Calorie floors, rate caps, the refusal to compute a goal weight below the healthy range for a person's height, and the refusal to run adult formulas for anyone under 18 are all implemented inside the calculation functions. A guardrail written only in the surrounding copy is a guardrail that a future edit will walk straight through.
• Locking every published result with a test. Each formula has hand-computed expected values in an automated test suite. A change that moves a published number fails the build before it can reach you, which is the only mechanism that reliably stops a quiet regression in a site nobody is paid to audit.

None of that requires a clinical qualification. All of it requires someone who will read the original paper instead of copying a number off another calculator, and who treats an unverified coefficient as a defect rather than a detail. That is the whole of the claim being made on this page.

Where this expertise stops

It stops at your body. A software engineer can tell you that the Navy tape equation was derived on a military population and drifts at the extremes, and can show you exactly which equation produced your number. He cannot tell you what your number means for you, because that requires examining you, knowing your history, medications and circumstances, and holding a registration that makes the advice answerable to someone.

So the site is built to stop at that line rather than blur it. Results describe the number, never the person. Where a judgement genuinely needs a clinician (the preclinical versus clinical obesity distinction introduced by the 2025 Lancet Commission framework, a very low reading, a refused goal, a child's growth percentile, a pregnancy), the page says so plainly and sends you to a human who can examine you. No page on this site carries a "medically reviewed" badge, because no page has been medically reviewed; that is set out in full on the medical review status page.

How these pages are produced and checked

The process is deliberately boring, and it is the same for every page. The formula is read from the primary source and implemented as a pure function with full float precision, rounded only at display. A test is written with values computed by hand from the published equation, plus boundary cases and an impossible input, and the test is committed before the page is. The formula is then written out on the page in full, with its units and coefficients, and a worked example walks the arithmetic through with real numbers so a reader can check the implementation without reading any code.

The prose is written around what the sources actually support. Where recognised classification systems disagree (the WHO standard and WHO Asia-Pacific BMI cut-offs, for instance), both are shown rather than one being chosen quietly. Where a figure is widely repeated but cannot be traced to a source worth citing, the page says so instead of printing it with false confidence. The full standard, including how sources are re-checked, how corrections are handled and how AI tools are used in drafting, is set out in the editorial policy, and every substantive change is recorded publicly on the changelog, corrections included. Terms used across the site are defined once in the glossary.

What the author does not do

• He does not give individual health advice. Questions about your own weight, your own result or your own health cannot be answered by this address, and answering them would be both unhelpful and irresponsible. Take the numbers to a doctor or an accredited practising dietitian.
• He does not medically review this content, and nobody else does either. Writing a page and reviewing it are different jobs, and one person cannot do both and call the second one review.
• He does not take supplement, diet-pill or weight-loss affiliate money. No affiliate relationship exists with any supplement, diet product, meal-plan or weight-loss program, and no payment has been or will be accepted to place, favour or soften a formula, a threshold or a recommendation.

Pages written by Rick Campbell

Every page below was written and built by him, and each carries the date of its last substantive content change. This list is generated from the site's own content registry rather than maintained by hand, so it cannot drift out of date or claim a page that does not exist.

Corrections and contact

Corrections are welcomed and acted on. If you believe a formula, a threshold, a citation or a claim on this site is wrong, write to hello@bodystats.co with the page and what you think is incorrect. A confirmed error in a calculation is fixed immediately, locked with a new automated test so it cannot return, and recorded on the changelog where anyone can see it. Being corrected is a better outcome than being confidently wrong, and this page exists so that you know exactly who is accountable for the difference.