Privacy

Updated 27 September 2026.

Calculations stay on your device

Every calculator runs in your browser. The numbers you type aren’t sent to our servers when you calculate.

What we store in your browser

To save you retyping, we keep your last inputs (units, sex, age, height, weight, activity level, tape measurements, pregnancy and cycle dates, today’s water glasses) and any results you save to “My numbers” in your browser’s localStorage, under keys starting with vm:. This data never leaves your device and isn’t visible to us. Anyone with access to this browser could see it, so clear it on a shared computer.

The AI explainer and Ask page

Only when you click “Explain” or “Ask”, the numbers shown on that calculator (or your typed question) are sent to an AI model through Vercel AI Gateway to generate the answer. We don’t attach your name, account or location, and VitalMetrics doesn’t keep a copy. Please don’t include personal details in questions. A short-lived, in-memory count of requests per IP address is used to stop abuse and is discarded automatically.

Analytics

We use Ahrefs Web Analytics, a privacy-friendly service that counts page views without cookies. It doesn’t receive anything you type into the calculators.

Medical disclaimer

VitalMetrics provides estimates for general education. It isn’t a medical device and doesn’t give diagnoses or treatment advice. Always talk to a qualified clinician about your health.