Editorial Policy

Every formula and figure on this site starts from a peer-reviewed study, a standards body or a professional guideline — never from another calculator site. For this site that means the energy-cost research of Minetti and colleagues for grade-adjusted pace, Jones and Doust for the 1% rule, Tanaka and colleagues alongside the Fox rule of thumb for maximum heart rate, the ACSM intensity classes for heart-rate bands, and the NIST unit definitions underneath every conversion. Each source is named on the Methodology page, with what it is used for, and named again on the page that uses it. If a number cannot be traced to a source on that list, it does not get published.

No calculator on this site is a black box. Every tool page prints its formula in plain sight next to the tool, works an example through it step by step, and shows the tables the subject needs. A reader with a pencil should be able to reproduce any headline result on the site — and where a page's construction involves a judgement, such as turning an energy-cost ratio into an equivalent flat pace, that step is written out and owned as the site's construction rather than quietly attributed to the underlying paper.

Some numbers on this site are exact arithmetic and some are estimates, and the pages say which is which, every time. Maximum heart rate from an age formula is an estimate with a wide individual spread, and the zone calculator says so next to the result. Step counts depend on a stride length the site cannot know, so they are computed from a stated default and labelled an estimate. Pace zones have no governing standard at all — the bands used here are a coaching convention, labelled as a convention on the page and on the methodology page. Dressing an estimate up as a measurement is the one shortcut this site never takes.

These tools compute; they do not prescribe. Nothing on this site tells you how hard to train, whether to train, or how to treat pain, illness or injury, and nothing here is a training plan. The zone calculator carries a disclaimer on the page itself: age-based heart-rate estimates can miss an individual's true maximum by a wide margin, medication such as beta blockers changes the heart-rate response, and anyone with a heart condition should talk to a doctor before training by zones. Training decisions belong to you, your coach and, where health is concerned, a qualified medical professional.

When an error is found — by me, or by a reader — the process is fixed: found, checked against the named source, fixed in the underlying code or data, and logged with a date. Corrections are dated when they are made, never backdated to a page's original review, and every page affected by a fix has its worked examples re-verified before it ships again. Readers can report an error on any figure through the report-an-error page; reports are read by the author personally, and a report that is right is answered with a fix, not an argument.

No advertising is running on this site today. If ads are enabled later, they will never change a formula, a table or a result: the numbers come from the published sources named above, no advertiser will see a page before publication, and no advertiser will have any say in what a calculator returns. The privacy policy will be updated on the same day advertising is enabled, to describe it truthfully.

AI tools are used as drafting and coding assistance in building this site, and that is disclosed openly rather than hidden — the full note is on the About page. No formula, factor or figure is published on an AI tool's say-so: each is checked against the source named on its page before publication, and responsibility for everything published here rests with the author, Ian Welkins.

Last reviewed: 10 November 2026