Editorial Policy

How we decide what to publish, where the numbers come from and what we do when something is wrong.

Last updated: October 1, 2026

What we publish

We cover cycling power, FTP, W/kg, speed, climbing, training load and aerodynamics, and nothing outside that. Each calculator answers one question, and no two pages target the same one. If a topic does not have enough substance for a full page, we do not publish a thin page for it.

How a page is written

Source first. The model, its assumptions and its limits are written down before any code, and the citations go on the sources page.
Calculate, then test. The formula lives in a calculation function with unit tests, as described on the methodology page.
Show the working. Example calculations run the real function, and tables are generated from it.
State the limits. Each page says what the number cannot tell you.
Label every benchmark. A figure is one of three things, and the page says which: a published table with its source named, a convention such as a test multiplier, or a rule of thumb that varies with age, sex and discipline. Numbers that are analyst estimates, such as professional climbing power, are called estimates. If a figure has no defensible source, it is left out.

Accuracy and corrections

If you find a wrong result, a broken formula or a misquoted source, email us through the contact page with the inputs you used and the answer you expected. We reproduce the problem, fix the calculation or the copy, and add a test so the error cannot return.

Updates

We revise a page when a formula changes, a source is superseded or a reader reports an error. Because worked examples come from the live calculation code, a formula fix updates every example on the site at once.

Limits of our advice

Results are planning estimates and not medical, coaching or laboratory advice. The terms of service cover this in full, and the about page explains why the site is built around one question. How we handle your data is in the privacy policy.