Privacy and cookies

Who is responsible

The controller is concrete.work. Contact: privacy@concrete.work.

What we process and why

Using the calculators. The measurements you type are calculated in your browser. We do not receive them unless you save a project. A link you copy to share a calculation contains the values you entered in the address.

Saving a project (optional). If you press Save, we store the calculation (shape, measurements and any prices you entered), the optional project name you type, the country and page, the dates it was created, changed and last opened, and a random private token that forms the project link. There is no account and we do not ask for your name or email. Anyone who has the link can open the project, so share it with care. Basis: your request (Art. 6(1)(b) and (f) GDPR).

Server logs. Our web server records your IP address, the date and time, the address requested, the response code and your browser type. We use them to keep the site secure, to prevent abuse (including limiting how many projects one visitor can save, which is counted in memory only) and to fix errors. Logs are kept for about two weeks. Basis: our legitimate interest in a secure and working site (Art. 6(1)(f) GDPR).

Cookies and similar technologies

Cookie _concrete_key: a session cookie set by us. It is deleted when you close the browser and contains a security token that protects the save function from forged requests. It is strictly necessary for the service you ask for, so it does not need consent.

Browser storage: “phx:theme” remembers light or dark mode if you choose one, “cc:notice-closed” remembers that you closed the notice offering another country’s version, and “cc:consent” remembers your cookie choice. They stay in your browser, are never sent to us, and you can delete them in your browser settings.

Analytics cookies are set only if you accept them where the law requires prior consent, and elsewhere until you switch them off (see “Analytics” below). You can change your choice at any time with “Cookie settings” at the bottom of every page. We do not use advertising cookies at this time; if we add them, we will update this page first and ask for your consent where the law requires it.

Analytics (with your consent where required)

We use Google Analytics 4 to count visits and see which pages are used, so we can improve the calculators. Google Analytics sets the cookies _ga and _ga_<ID> in your browser and sends information about your visit (pages viewed, which calculator functions you use such as saving or sharing a calculation, approximate location, device and browser, a random identifier) to Google. The measurements you type and the private link of a saved project are removed from the address before it is sent. According to Google, Google Analytics 4 does not log or store IP addresses. The provider is Google Ireland Limited for visitors in the EEA, the United Kingdom and Switzerland, and Google LLC elsewhere; data may be processed in the United States.

Where the law requires your consent first (the EEA, the United Kingdom, Switzerland, Canada, Brazil, South Korea, and whenever we cannot tell where you are), nothing is loaded and no analytics cookie is set unless you accept. In other countries analytics starts automatically and you can switch it off at any time with “Cookie settings” at the bottom of every page. To decide this we use the country that Cloudflare derives from your IP address when the page loads; we do not store it. If you reject, or withdraw your consent later, the analytics cookies are deleted. A Global Privacy Control signal sent by your browser is treated as a rejection everywhere. We do not use Google Signals, advertising features or ad personalization. Basis: your consent where it is required (Art. 6(1)(a) GDPR and the rules on cookies and similar technologies), and otherwise our legitimate interest in understanding how the site is used (Art. 6(1)(f) GDPR), to which you can object at any time.

Providers and transfers

Cloudflare, Inc. delivers and protects the site (content delivery and protection against attacks). Your requests, including your IP address, pass through its network.

Hetzner hosts our server, which is located in Ashburn, Virginia, United States. Your data is therefore processed in the United States. Where data from the EEA, the United Kingdom or Switzerland is transferred there, the transfer relies on the mechanisms that apply to our providers, such as the EU–US Data Privacy Framework or standard contractual clauses. You can ask us for details.

We do not sell personal data.

How long we keep data

Server logs: about two weeks. Saved projects: until you ask us to delete them, or automatically after 24 months in which nobody has opened or changed them. Session cookie: until you close the browser. Analytics cookies: up to two years, and Google keeps the analytics data for the period set in our account, at most 14 months. Browser storage: until you delete it.

Your rights

Depending on where you live (for example under the GDPR, the UK GDPR or the Swiss data protection act) you can ask for access to your data, correction, deletion, restriction, a copy, and you can object to processing. Where we rely on consent you can withdraw it at any time. You can also complain to your data protection authority.

To exercise your rights write to privacy@concrete.work. If you saved a project, include its link: it is the only way we can find it, because we hold no name or email.

Changes

We may update this page. The date at the top shows the latest version.