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, the only data processed is what any web server and content delivery network records in order to serve a page and stay secure:

• 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.
• Nothing else — there are no accounts, no contact forms, no comment fields, and no user-submitted content.

Your calculations stay on your device

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.

The address of a page you visit does appear in standard access logs, like any web address. For that reason, avoid putting information you consider sensitive into a calculator whose link you intend to share.

Cookies and local storage

The site sets no cookies and uses no 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 and is never sent to the operator.

Analytics

The site is built to support privacy-respecting, cookieless product analytics (PostHog), but analytics is currently inactive in production: no analytics key is deployed, so no analytics data is collected and no analytics script loads.

If analytics is enabled in the future, it would record only aggregate, non-identifying usage events — such as which calculator was opened and the interface language — through a first-party endpoint at api.calcu.lol. It would never receive the values you enter or the query string of a calculator's address. This section will be updated when that happens, and the legal basis would be 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 described above as processors:

• Cloudflare, Inc. — content delivery, DNS, and security, protecting the origin server and serving cached pages.
• The origin hosting provider — runs the web server that returns pages.
• PostHog, Inc. — product analytics, only if analytics is later enabled (currently inactive).

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.

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. Logs are kept only for a short period for security and troubleshooting, and are then deleted or anonymized by the providers under their standard retention practices.

Global Privacy Control

The site honors the Global Privacy Control (GPC) signal and publishes a machine-readable statement at /.well-known/gpc.json. Because the site does not sell or share personal data, there is nothing to opt out of: the GPC signal is honored by default for every visitor.

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 a provider's short-lived logs to your identity.

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. It knowingly collects no personal data from anyone, including children.

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.