About HealthTools
HealthTools publishes free browser-based calculators for everyday numbers: stimulant clearance, training heart rate, body-composition estimates.
Every page discloses its formula, names the published source it came from, and prints worked examples computed by the same code that runs in your browser.
We do not currently have a clinical reviewer on staff. Where a number would require clinical judgement, we publish the arithmetic only and say so plainly. That limitation is stated on each page rather than hidden.
No account, no paywall, no data collection. Contact details are on the contact page.
The site is run by one operator who writes the code and the copy, and who reads every reported error personally. That is a limitation as well as a feature: it means updates are slow, and it also means nothing here was produced without someone reading it.