Privacy Policy

What we collect

Directly, nothing. There is no sign-up, no login, no contact form and no newsletter, so there is no name, email address or account to hold. We do not embed advertising and we do not load social widgets, or fonts and scripts from third-party networks — with the single exception described in the next section.

Analytics

The site loads Google Analytics in order to count visits and see which converters people actually use. Google receives the usual measurement data: the page address, the referring page, your approximate location derived from your IP address, and your browser, device and language. This is enough to tell us that a page was opened. It is not enough to tell us who opened it, and we make no attempt to find out.

Google acts as our processor for this and may use the data as described in its own privacy policy. If you would rather not be counted, any tracker blocker, Google's official opt-out add-on, or a browser set to block third-party scripts will stop it. The converter is unaffected — analytics is loaded separately from the code that does the arithmetic, and every page works identically with it blocked.

What happens to the values you type

They stay on your device. Every conversion is computed by code running in your own browser, so your values are never transmitted to us or to anyone else — which is a stronger guarantee than a promise not to look at them: there is nothing to look at.

Analytics is not an exception to this. The converter puts what you type into the address bar so a link can be shared, which means the value appears in the page URL — and a measurement script would normally report that URL in full. Ours does not: it is given the page path only, with the query string stripped before anything is sent. Google is told you opened the length converter; it is not told what you converted.

Cookies and local storage

Google Analytics sets its own cookies on your device — _ga and a second cookie named for this site's measurement ID. Their purpose is to tell a returning visit from a new one, they contain a randomly generated number rather than anything about you, and they expire on their own. Blocking them, or clearing your site data, costs you nothing: the site does not read them and does not behave differently without them.

Nothing else here uses cookies. Your light-or-dark theme choice is stored in your browser's local storage instead — it never leaves your browser and is not an identifier.

A service worker also caches pages you have visited so the site keeps working offline. That cache holds the same public pages anyone can download, lives only on your device, and is cleared along with your site data.

Server logs

The site is a set of static files served by a hosting provider. Like every web server, that provider records standard request information — such as the IP address making a request, the page requested, and the browser's user-agent string — for delivery, security and abuse prevention. We do not build profiles from those logs, connect them to anything you type, or use them for advertising.

Security

Because we hold nothing about you, there is no store of personal data to breach — which is the most effective security measure available to us and the reason the site is built this way. Beyond that, pages are served over HTTPS, and the site ships a strict Content Security Policy that confines scripts, styles, images and fonts to its own origin, with Google's analytics domains as the only exceptions and no other outbound connection permitted at all. An injected or compromised script would have almost nowhere to send anything.

If you believe you have found a security issue, please report it to the address below before disclosing it publicly.

Children

The site is a general-purpose reference tool that collects no personal information from anyone, of any age.

Changes to this policy

If this policy changes, the date at the top of the page changes with it. Any change that would involve collecting data we do not collect today would be described here plainly rather than buried in a revision.