Editorial Policy
Fitness Calculator publishes ten free calculators. Guides sit behind them. Every calculator page names its equation, shows its inputs, works a real example all the way through, and says where the number stops being useful. This page tells you who writes that, how it gets checked, and what the site earns.
Who writes this site
Rowan Hale is the pen name of the one person who builds and maintains the site, as the About page explains. Ten calculators, one person. No medical, dietetic or exercise-physiology qualification sits behind the writing, and nothing here is clinically reviewed. A citation is evidence for a claim. It does not promote the author to a healthcare professional, so treat these pages as reference material and take decisions about your own health to someone qualified to make them with you.
What each calculator runs
- BMI divides weight by height squared. It explains the adult screening categories along with what they miss.
- BMR runs Mifflin-St Jeor, the 1984 Roza and Shizgal revision of Harris-Benedict, and Katch-McArdle side by side. The gap between them is printed too.
- TDEE estimates resting energy from Mifflin-St Jeor. Then it applies a stated activity multiplier that you pick yourself.
- Calories builds on that same TDEE figure. The deficit and surplus adjustments are worked examples, never diet prescriptions.
- Macros splits a calorie target into protein, carbohydrate and fat. Several splits fit the same target. The page shows you why they behave differently.
- Body fat uses the traditional Navy circumference equations. The estimate comes from a tape measure, and it carries no official military standing.
- Army body composition runs the waist-to-height ratio from Army Directive 2026-13. The directive took effect 7 July 2026.
- AFT scores the five events against the Army Fitness Test tables approved 15 May 2025. The sex-neutral combat standard is included.
- Ideal weight compares the Devine, rounded Robinson, Miller and Hamwi equations against an adult BMI-based range; the midpoint is the average of four equations, which is exactly as personal as that sounds.
- Water intake uses a rough weight-and-exercise rule and reports an illustrative total-water figure, food and drinks included. The National Academies’ figure answers a different question again, and a requirement measured on you is a third thing altogether.
Sources and uncertainty
Calculator pages link to the research paper, or to the organisation publishing the guidance under discussion. Where the site adds an assumption of its own, such as an activity multiplier or a fixed exercise allowance, it is labelled as an assumption and kept visibly apart from the published equation. A figure carried to one decimal place is still an estimate. Precision on your screen says nothing about accuracy for your body.
Checks and corrections
The 13 September 2026 tool update was tested against worked examples, metric and imperial conversions, missing and invalid inputs, and the height boundary where the ideal-weight formulas stop behaving. Those tests cover the implementation. Clinical validity is a separate question, and they leave it alone.
Every calculator page carries its update date. If a formula, a source or a displayed result looks wrong to you, report it with the calculator name and an example that reproduces the problem. Please keep your personal medical details out of that message.
Who these calculators are for
They are general education for adults. The BMI categories here apply from age 20 upward. Care for children, pregnancy, breastfeeding, eating-disorder recovery or any medical condition needs a clinician, and a web page cannot plan it. Where a professional has already given you a fluid or nutrition plan, follow theirs. The medical disclaimer in the footer of every page sets out the full limits.
How the site is funded
All ten calculators are free. They run in your browser the moment you open the page. Google AdSense sells the advertising you see here, and no advertiser has any say over what these pages say. Your calculator inputs stay in your browser. Consent controls run before any advertising or analytics cookie is set, and the privacy policy in the footer covers analytics and advertising separately.
AI assistance and review limits
The site uses AI assistance for research, editing and software development. Editorial responsibility rests with the site operator, and the credentials question is answered above.
On 13 September 2026, 18 guides were revised to separate estimates from measurements, drop health guarantees that outran their sources, and point readers at the underlying material. Those corrections covered hydration risk, the limits of BMR and calorie-intake figures, body-fat accuracy, waist measurement sites and muscle-gain predictions. Charts that implied a fixed outcome came out of their articles. On 10 October 2026 the guides and policy pages were edited again, this time for how they read, with the claims left as they stood.