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PeriodicDeck

Privacy Policy

Last reviewed 30 July 2026.

This is a static reference site. Pages are pre-built and served as files, there is nothing to log into, and the great majority of visits leave no record attached to anyone. What follows is the complete list of exceptions.

The four places data is involved at all

Aggregate page counts. The site records how many times each page is viewed, through privacy-preserving analytics that set no cookies, build no cross-site profile and store no identifier that could single you out on a later visit. What comes back is a count per page, per day. It is used to decide which element pages deserve more work.

Hosting logs. The host, Vercel, keeps short-lived request logs containing IP addresses and browser user-agent strings, in the ordinary way that any web server does, for delivery and abuse-prevention purposes. Those logs are not read for analytics and are not combined with anything else here.

The newsletter, if you subscribe. Subscribing stores the email address you type and the date you gave it, through Brevo, which handles the sending. A welcome message goes out immediately; after that it is the occasional note and nothing else. Nothing further is asked for and nothing else is inferred. Every message carries an unsubscribe link that removes the address rather than flagging it, and an address is never sold, rented, shared or used to reach you about anything other than this site.

A purchase, if you make one. Payment for the printable pack is handled entirely by Stripe. Card details are entered on Stripe's own infrastructure and never reach this site or its host, and no record of the payment is sent back to this site either. The order is read from Stripe's own dashboard, and the file is sent by hand to the address given there. Stripe collects the name, billing details and payment information required to process a card transaction, and Stripe's own privacy terms govern that. There is no account to create and no stored payment method.

What the calculators do with what you type

Nothing leaves your device. The molar mass, percent composition, equation balancing and configuration tools all run as JavaScript in your browser, computing from data that was shipped with the page. Formulas and equations you enter are not transmitted anywhere, not logged and not retained after you close the tab.

What is deliberately absent

  • No advertising of any kind, and therefore no ad-network cookies, no retargeting pixels and no data broker in the chain.
  • No user accounts, no comments and no user-submitted content. There is no profile to build because there is no profile.
  • No social media embeds or third-party widgets that would load a tracker alongside a page.
  • No sale or sharing of personal information, in the sense that phrase carries under California law, because there is no personal information collected that could be sold.

Mail you send

An email sent to the address on the contact page arrives in an ordinary mailbox and is kept for as long as it is useful — typically until whatever it raised is resolved, and longer where it produced a correction that someone might later query. The form on that page is delivered by Formspree, which forwards what you write to that same mailbox and holds a copy of it in doing so. Either way, messages are not added to the newsletter list.

Children

Nothing here is directed at children under 13, and no information is knowingly collected from them. The site is used by school-age students constantly, which is precisely why it asks for nothing in order to work.

Your rights, and how to use them

If you are in the UK, the EU, California or anywhere with comparable law, you can ask what is held about you, ask for a copy, ask for it to be deleted, and withdraw consent for the newsletter at any time. In practice the answer for most readers is that nothing is held.

Requests go to the contact address. There is no identity-verification process beyond replying from the address in question, because an email address is the only identifier there is.

If this policy changes materially, the date at the top changes with it.