Privacy
Nothing you type or drop here is sent anywhere
This site is a set of static files. There is no application server, no database and no account system. Two third-party scripts load on every page: Google AdSense, which serves the ads, and Cloudflare Web Analytics, a cookieless counter injected by the host. Both are described in Advertising and Analytics below. Everything else — including your STL files — stays in your browser, which you can confirm in the network panel.
What is collected
| Data | Collected? | Detail |
|---|---|---|
| Calculator inputs | No | They live in the page and in the URL you are looking at. They are never transmitted. |
| STL files | No | Read with the browser File API, parsed in a Web Worker in the same tab, then discarded. There is no upload endpoint. |
| Cookies | Advertising only | This site sets none of its own — not for preferences, not for measurement. Google's ad script may set cookies or read device identifiers; see Advertising. |
| Analytics | Aggregate only | No Google Analytics, no Plausible, no pixel, no per-visitor profile. Cloudflare's host-level Web Analytics counts page views without cookies — see Analytics. |
| Third-party scripts | Two | Google AdSense (ads) and Cloudflare Web Analytics. No third-party fonts, CDNs or social widgets; every other request goes to this domain. |
| Accounts | No | There is nothing to sign up to. |
What the hosting layer sees
Like every website, the servers that deliver these files see the request: the page you asked for, your IP address, your browser's user-agent and the time. The site is designed to be hosted on a static platform (Cloudflare Pages), which keeps standard request logs for security and abuse purposes. Those logs are the host's, not ours; we do not build profiles from them. Two scripts on the page talk to a third party — the Google advertising script and Cloudflare's cookieless counter — and both are described below.
If you want to confirm the file-handling claim, open your browser's developer tools, switch to the Network tab, and drop an STL on the checker. No request appears.
Sharing links
Calculator inputs are written into the URL as you type — for example /3d-printing-cost-calculator/?volume=120&material=pla. That is how a calculation becomes shareable without a server. Treat a shared link the way you would treat any URL: it contains your numbers, including any price you typed.
Advertising
This site is free and is paid for by advertising, delivered through Google AdSense (publisher ID pub-1537560823958390). A script from pagead2.googlesyndication.com is loaded on every page.
Google and its partners use cookies and device identifiers in connection with ads on this site. They are used to:
- serve personalised ads based on your prior visits to this and other sites, or non-personalised ads where you have opted out or where consent is not given — in which case ads are selected from page content and general location rather than your history;
- cap how often the same ad is shown to you (frequency capping);
- measure ad performance in aggregate; and
- detect invalid traffic and prevent ad fraud.
You can turn off personalised advertising, or reset the advertising identifier Google associates with your browser, here:
- Google Ads Settings — manage and opt out of personalised ads.
- Google Ad Preferences — see and change the interest categories Google has inferred.
You can also refuse cookies at the browser level — every major browser lets you block third-party cookies or clear them after a visit — and use a content blocker. Blocking the ad script does not break anything on this site: the calculators, converters and the STL checker run without it. Google's own explanation of how it uses data from partner sites is at policies.google.com/technologies/partner-sites.
No personalised advertising is served on the basis of the contents of a file you drop on the STL checker. Those files never leave your device, so neither Google nor anyone else can see them.
Analytics
Page views are counted by Cloudflare Web Analytics, which the host (Cloudflare Pages) injects into every page as a small script from static.cloudflareinsights.com. It is cookieless: no cookie is set, no identifier is stored in your browser, and there is no cross-site profile or individual visitor history. What it records is aggregate — which pages were viewed, the referring site, the country and the browser type, derived from the request your browser already sends. It is used only to see which pages are worth maintaining.
Because it sets no cookies and stores no identifier, it is out of scope of the EU cookie-consent rule, which covers storage on your device rather than aggregate server-side counts. A content blocker or blocking third-party scripts stops it and the site works identically. There is no Google Analytics, no session recording and no advertising pixel beyond the AdSense script described above.
Contact
Questions about this policy: hello@stlcheck.com. Your calculator inputs and STL files are never transmitted, so there is nothing of that kind to delete. For advertising data, use the Google controls linked under Advertising.
Last updated 2026-10-23.
Frequently asked questions
Does the STL checker upload my model?
No. Parsing happens in a Web Worker on the same page. You can load a file, disconnect from the network, and the analysis still completes.
Do you use cookies for preferences?
The site sets no cookies of its own — your currency choice is stored in the URL, not in a cookie. Google's advertising script may set ad cookies, which the Advertising section covers.
Will you add analytics later?
Page views are already counted by Cloudflare's cookieless Web Analytics, described above. There are no plans to add Google Analytics, session recording or any pixel that follows you across sites.