About

Health math, cleaned up.

TheHealthTools.com is a small, independent project that does one thing well: take the formulas your doctor uses every day, run the math cleanly in your browser, and explain the result in language that actually helps. No accounts. No data leaves your device. No ads pretending to be calculators.

Why we exist

Most online health calculators are gateways into a paid funnel. They bury the math under upsells, ask for an email before showing the result, or drop ads where the answer should be. We wanted the opposite — the actual number, the actual category, and an honest explanation of what it means and (more importantly) what it doesn't mean.

Every calculator on this site is based on a published clinical formula from a recognized health authority. We cite the source on each page and link to the original guideline document. If a formula is updated — like the CKD-EPI 2021 race-free eGFR equation that replaced the 2009 version — we update with it.

How we stay free

The site is supported by Google AdSense. Ads are clearly labeled, never appear inside a calculator's input or result area, and never influence the order or content of the tools we publish. That's a permanent commitment, not a slogan.

Editorial principles

• Cited sources. Every calculator names the original formula and the issuing body (WHO, CDC, NHS, AHA, KDIGO).
• Clinical review. A licensed clinician reviews each tool and its supporting copy on a quarterly cadence. See the medical review page.
• No diagnoses. We provide information, not medical advice. Every result page reminds you to consult a qualified professional before acting on the number.
• No data collection. Calculator inputs never leave your browser. Optional progress tracking is stored locally on your device and you can wipe it with one click.
• Plain English. If a result needs to be explained, we explain it without jargon. If jargon is unavoidable, we define it.

Who's behind the tools

The site is currently maintained by an independent team — not by a licensed clinician. We think it's more useful to say that plainly than to invent credentials, so we don't. Read the full editorial process for what this site is and isn't.

Get in touch

Spotted an error in a formula? Have a clinical guideline update we should reflect? Want a calculator we don't have yet? Reach us via the contact page. We read every message.