Rowan Hale

Updated 10 October 2026

Rowan Hale is a pen name. One person runs this site, writes the calculator explanations and the guides and handles the corrections, and that person holds no medical, dietetic or exercise-physiology qualification. It is a byline.

What this work covers

11 calculators, and for each one the formula underneath it, the inputs it asks for, the unit conversions it runs and how far you can reasonably push the number it gives back. The guides carry the worked examples and the links to source material.

Research, writing, editing and code changes here may use AI assistance. And the September 2026 audit that revised the health claims and tested every calculator's behaviour was an audit of arithmetic and wording. Independent clinical review is a different exercise, and this site has not had one.

Qualifications and limits

Read these pages as reference arithmetic, not as clinical advice. Linking a study makes a claim easier for you to inspect; it does not make my reading of that study correct, or make the result it points to right for your situation.

Symptoms, medication, pregnancy, an eating disorder or a prescribed diet all need an appropriately qualified professional, and that applies even when a number on this site looks reassuring. The medical disclaimer sets out the boundaries.

Checks and corrections

Every calculator gets checked against worked arithmetic, its unit conversions and its input limits. That tests whether the code does what the formula says. Whether the formula itself predicts your physiology is a separate question, and the pages say where the evidence for that is thin.

The editorial policy records the methods and the September 2026 content corrections. If you spot an error, send it through Contact with the URL and either a source or a made-up example. Leave your own medical records out of it.