Privacy Policy

Last updated: July 23, 2026

This policy describes what data CostMirror processes and on what basis. If you have questions, please contact the data controller.

1. Data controller

The data controller is InnoMeth Patryk Wójcik, al. Jana Pawła II 71/12, 42-202 Częstochowa, Poland (Polish Tax ID / NIP: 573-294-78-59). Contact: patryk@innometh.pl.

2. What data we process

CostMirror does not require registration or an account. The Real Cost and Time Cost calculators work entirely in your browser - the amounts, salary, and results you enter are never sent to any server.

3. Mirror Past - data sent to our server

The Mirror Past feature sends the data needed to run the simulation (amount, frequency, start date, selected instrument, optional habit name) to the CostMirror server solely to calculate the result in real time. As currently implemented, this data is not permanently stored in the CostMirror database and is not passed to Google Analytics.

4. Google Analytics 4

We use Google Analytics to analyze how CostMirror is used and to improve the product.

Scope of data shared with Google Analytics (only after your consent):

• technical information about your device and browser (e.g. browser type, operating system, screen resolution)
• information about page views and navigation between them
• general information about interactions with the calculators (e.g. which calculator type was completed, the selected instrument category, the general outcome: gain/loss/flat), as described in the technical documentation
• cookie identifiers created by Google Analytics after you give consent (_ga, _ga_*)

Legal basis: Your voluntary consent (Article 6(1)(a) GDPR), given by clicking "Accept analytics" in the cookie banner or in the cookie settings.

Voluntariness: Giving consent is entirely voluntary. Refusing does not restrict access to any calculator or feature of CostMirror.

Data recipient: Your data is processed by Google. For users in the European Economic Area, the entity responsible for the Google Analytics service is Google Ireland Limited (Gordon House, Barrow Street, Dublin 4, Ireland). Full details on how Google Analytics processes data are available in Google's current documentation.

Transfers outside the EEA: Google may transfer data to countries outside the European Economic Area, including the United States. Under Google's current terms, such transfers rely on legally recognized mechanisms (such as the European Commission's adequacy decision under the EU-U.S. Data Privacy Framework, or standard contractual clauses). Details of the current mechanism are available in Google Analytics' official documentation.

Retention period: We configure the Google Analytics data retention period following privacy-first recommendations in the Google Analytics admin panel (see the technical documentation). The _ga and _ga_* cookies have a default lifetime of up to 2 years, unless you remove them earlier.

Withdrawing consent: You can withdraw your consent at any time in "Cookie settings" in the site footer.

Data we intentionally do not send to Google Analytics:

• amounts entered in the calculators
• salary or income
• portfolio value or total contributions
• exact return (ROI) or exact dates you selected
• text entered in the instrument search
• data that could directly identify you (name, email, phone number)

We cannot guarantee that Google Analytics technology is fully anonymous - Google may, under its own terms, process technical browser data as personal data under the GDPR. That is why we only enable Google Analytics after your explicit consent.

5. Your rights

You have the right to access your data, to have it corrected or deleted, to restrict its processing, to data portability, and to object to processing - to the extent we process data that can be attributed to you. For Google Analytics, you can also use Google's own tools to manage your data.

6. Complaint to a supervisory authority

You have the right to lodge a complaint with a data protection supervisory authority. In Poland, this is the President of the Personal Data Protection Office (ul. Stawki 2, 00-193 Warsaw).

7. Changes to this policy

This policy may be updated - for example due to changes in the Google Analytics configuration or in applicable law. The current version is always available on this page, together with the date of the last update.