Privacy policy

HydrationGuide is operated by Reede Taylor, based in the Netherlands, as the data controller for the small amount of processing described here. You can reach us through the contact page.

Every calculation runs in your browser. Your weight, training time, drinks, and any other input are never transmitted to a server, and we never see them.

So that a tool remembers what you last entered, each calculator saves its own inputs in your browser's local storage under a key beginning hg: — for example hg:water-inputs. This data stays on your device, is readable only by this site, and is removed if you clear your browser's site data. The cookies and storage page lists every key.

We use Vercel Web Analytics to count page views and see which calculators get used. It sets no cookies, does not follow you between websites, and produces no profile of you. Visitors are counted using a hash derived from the incoming request rather than a stored identifier, and that session marker is discarded within 24 hours.

The lawful basis is legitimate interest (Article 6(1)(f) GDPR): we need a basic sense of whether the site is useful, and this is the least intrusive way we know of to get it. Because it stores nothing on your device and cannot identify you, we do not ask for consent for it. If we ever add advertising or affiliate tracking that does set identifiers, that will require your consent and this page will change before it happens.

Vercel Inc. acts as our processor for this data and for hosting the site. Their processing is covered by their data processing agreement and standard contractual clauses for transfers outside the EEA.

Messages sent through the contact form are delivered by Formspree, which passes them to our email inbox. We receive whatever you choose to put in the message, including the email address you give us so we can reply. We keep correspondence only as long as needed to deal with it, and we do not add you to any mailing list.

• No advertising networks, retargeting, or tracking pixels
• No selling or sharing of data with third parties
• No accounts, passwords, or stored personal profiles
• No requests to any third-party domain when you load a page

Under the GDPR you have the right to access, correct, delete, restrict, or object to processing of your personal data, and to data portability. In practice we hold almost nothing about you: the analytics data is anonymous and cannot be traced back to an individual, so there is usually nothing to retrieve or erase. If you have contacted us, get in touch and we will delete the correspondence.

You can also complain to a supervisory authority. In the Netherlands that is the Autoriteit Persoonsgegevens.

The calculators are built for adults and are not directed at children. We do not knowingly collect any personal data from children.

If this policy changes materially, the date at the top of the page changes with it. There is no mailing list to notify, so the date is the honest signal.