Privacy Policy

Who is responsible

The site is operated by David de León (GitHub: @dvddvd300), who is the data controller for the purposes of the EU General Data Protection Regulation (GDPR). Because this is a personal, non-commercial project, there is no company entity.

You can reach the operator through the GitHub profile linked above. There is no support email address.

What data is processed

The site is designed to collect as little as possible. In normal use, only the following data is processed:

• Technical request data in server and CDN access logs: your IP address, the requested address, the date and time, the page that referred you, and your browser's user-agent string.
• Occasional security reports from your browser (Content Security Policy violation reports), which include the address of the page concerned.
• Cookieless usage analytics events, described in the Analytics section below.
• Nothing else — there are no accounts, no contact forms, no comment fields, and no user-submitted content.

Calculations run in your browser

Every calculator runs entirely in your browser. The numbers you type are reflected into the page's address so a result can be shared or bookmarked, but they are not transmitted to a server for processing and are not stored as calculation content.

Because the numbers are part of the page's address, opening or reloading such an address sends it, values in the query string included, to the site's CDN and web server, and a browser security report about that page sends it to the web server too. It can therefore appear in the server and CDN logs described under “Legal basis and retention”. This happens even if you never share the link; analytics never receives the query string. Avoid entering information you consider sensitive into a calculator, since the address carries the values.

Cookies and local storage

The site sets no cookies and uses no persistent tracking or advertising identifiers. A small amount of your browser's local storage may be used to remember your own preferences — such as recently used or favorited calculators. That information stays on your device; the stored list itself is never sent to the operator.

Analytics

The site uses cookieless product analytics from PostHog (PostHog, Inc., United States), received through api.calcu.lol, a calcu.lol address operated by PostHog. It collects individual usage events, such as page views, which calculator was opened, the interface language, share, copy, favorite and download actions, and automatically recorded clicks on interface controls with their labels, together with technical details such as browser type, language, time zone and screen size, and an approximate location that PostHog derives from your IP address; the IP address itself is not stored. Each event is linked only to a temporary random ID that lasts while the site stays open in that browser tab (moving between pages keeps it; reloading or opening the site in a new tab starts a new one), and the events are analysed only in aggregate.

It never receives the values you enter: page addresses are recorded without their query string or fragment, which is where a calculator keeps those values. It sets no cookies and stores nothing on your device; the temporary ID is discarded when you close the tab, reload or leave the site, but that does not delete events already sent. Events are kept for up to seven years, the analytics provider's retention period, and then deleted. They are stored in a PostHog project the operator uses for several small sites. If your browser sends a Do Not Track or Global Privacy Control signal, no analytics events are sent. The legal basis is legitimate interest (Article 6(1)(f) GDPR) in understanding, in aggregate, how the site is used.

Service providers

To deliver the site, the operator relies on the following providers, which may handle the technical request data and analytics events described above as processors:

• Cloudflare, Inc. — content delivery, DNS, and security, protecting the origin server and serving cached pages.
• The origin hosting provider — supplies the servers on which the operator runs the web server that returns pages.
• PostHog, Inc. (United States) — cookieless product analytics, received through api.calcu.lol, a calcu.lol address operated by PostHog.

International data transfers

Some providers named above are based in, or operate infrastructure in, countries outside the European Economic Area, including the United States. Where technical request data is processed in such countries, the transfer relies on the providers' standard safeguards, such as the EU Standard Contractual Clauses. Analytics events are processed and stored in the United States by PostHog under its contractual safeguards, such as the EU Standard Contractual Clauses.

Legal basis and retention

Server and CDN access logs are processed on the basis of legitimate interest (Article 6(1)(f) GDPR) in operating a secure, reliable website. The operator keeps server logs for 7 days for security and troubleshooting and then deletes them; Cloudflare keeps its CDN logs under its own retention practices. Analytics events are processed on the same legal basis and kept for up to seven years, as described under Analytics above.

Global Privacy Control

The site honors the Global Privacy Control (GPC) signal and publishes a machine-readable statement at /.well-known/gpc.json. The site does not sell personal data or share it for advertising or cross-context behavioral advertising. If your browser sends GPC (or Do Not Track), the analytics described above is switched off entirely: no analytics events are sent.

Your rights

Under the GDPR you have the right to access, correct, erase, or restrict the processing of your personal data, to object to processing, and to data portability. In practice the site holds almost no personal data about you: there is no account, and it cannot connect an IP address in the short-lived server and CDN logs to your identity. Analytics events carry only a random ID that changes whenever the site is reloaded or opened in a new tab, so the operator cannot single out the events that relate to you (Article 11 GDPR).

To exercise a right, or to ask a question about this policy, contact the operator through the GitHub profile above. You also have the right to lodge a complaint with your local data protection authority.

Children

The site is a general-audience educational tool and is not directed at children. The limited technical data and analytics described above may be processed for visitors of any age; the site does not ask visitors for their age or any other personal information.

Changes to this policy

This policy may be updated as the site changes. The date at the top reflects the current version, and any material change to how data is processed will be reflected here before it takes effect.