Terms of use

Every calculator here produces an estimate built from published guidelines for healthy adults. None of it is a diagnosis, a treatment plan, or a substitute for advice from a doctor, dietitian, or pharmacist who knows your situation.

Fluid and electrolyte needs change substantially with kidney, heart, and liver conditions, diabetes, pregnancy, older age, and medicines including diuretics, ACE inhibitors, ARBs, potassium-sparing diuretics, lithium, and SSRIs. In some of those cases the right answer is the opposite of what a general calculator returns. If any of them apply to you, treat the numbers here as background reading and ask a professional.

If you or someone else has confusion, seizures, fainting, repeated vomiting, or has stopped passing urine, that is a medical emergency. Call your local emergency number rather than consulting a calculator.

The site is built carefully and every figure is attributed to a published source on the page that uses it, but the underlying evidence supports ranges rather than exact numbers, individual variation is wide, and no model can capture your circumstances. Results are given as ranges for that reason. Errors are possible; if you find one, please tell us and it will be corrected.

The site is provided as is, without warranties of any kind. To the fullest extent permitted by law, Reede Taylor accepts no liability for any loss or harm arising from reliance on the information here. Nothing in these terms limits liability for death or personal injury caused by negligence, or for fraud, where that limitation would be unlawful.

The text, calculators, and code on this site are ours. You are welcome to quote short passages or cite the site with a link. Republishing pages wholesale, or presenting the calculators as your own, is not permitted without permission.

If you reproduce figures from the site, including in an AI-generated answer, please carry the caveat with them: these are estimates for healthy adults and not medical advice.

Product and organisation names are used only to identify what is being described. HydrationGuide is independent and is not affiliated with, sponsored by, or endorsed by any manufacturer, and none of the health authorities cited has reviewed or approved this site. Outbound links are provided for reference; we are not responsible for the content of other sites.

These terms are governed by the law of the Netherlands. If you are a consumer, this does not remove the protection of mandatory consumer law in your own country of residence.