Privacy & Cookie Policy

Version 1.0 — effective 11 October 2026

This policy explains how personal data is processed when you use metcalc.info (the "Site"), including the calculator widget that other websites embed from metcalc.info (the "Widget"). It does not apply to metcalc.ru, which is a separate website with its own policy.

1. Who is responsible

The controller of your personal data is:

FORZATS EDPK („ФОРЗАЦ“ ЕДПК)
UIC (ЕИК) 208929400, VAT BG208929400
58 Slavyanska St., Dabovo 6178, Maglizh Municipality, Stara Zagora Province, Bulgaria
Email: box@flyleaf.su · Phone: +359 879 441 559

We have not appointed a data protection officer, as the law does not require it for our activities. For any privacy question or request, write to box@flyleaf.su.

2. What we process, why, and on what legal basis

You can use the Site without an account and without giving us your name, email or any other details. We process only the data described below.

2.1 Server logs

When your browser requests a page, our web server records:

• your IP address;
• the date and time;
• the requested URL and the referring page;
• your browser's user-agent string;
• the response status.

Purpose: delivering the Site, keeping it secure, preventing abuse and investigating faults.

Legal basis: our legitimate interest in operating a secure and working website (Art. 6(1)(f) GDPR).

Retention: the access log has a fixed maximum size. Once it is full, the oldest entries are deleted automatically, which at our traffic happens after a few days. Application error logs, which normally contain no IP address, are deleted after 14 days.

2.2 Error reports (Site and Widget)

If an error occurs in your browser while you use the Site or the Widget, a technical error report is sent to our error-monitoring service, Sentry. The report contains:

• the error message and where in our code it occurred;
• the page URL;
• your browser and operating-system version;
• a short record of the actions that led to the error, such as page navigation and requests made by the page;
• your IP address, which Sentry receives with the report.

We do not send performance or usage data to Sentry, and Sentry sets no cookies.

Purpose: finding and fixing errors.

Legal basis: our legitimate interest in keeping the Site working correctly (Art. 6(1)(f) GDPR).

Retention: up to 90 days.

2.3 Rating votes

If you rate a calculator page, we keep a hashed form of your IP address for 6 hours to prevent repeated votes. The rating itself is stored only as an average and a vote count, not linked to you.

Legal basis: our legitimate interest in protecting the ratings from manipulation (Art. 6(1)(f) GDPR).

2.4 Analytics (only with your consent)

If you accept analytics cookies, we use Google Analytics 4, provided by Google Ireland Limited. It shows us which calculators are used and how the Site performs.

What Google receives: your interactions with the Site, device and browser data, and your IP address. For visitors from the EU, Switzerland and the UK, Google uses the IP address only to derive an approximate location and does not log or store it.

Settings: we have disabled Google Signals and the sharing of analytics data with Google for advertising purposes. User- and event-level analytics data is deleted after 14 months.

If you do not consent: Google Analytics is not loaded and no data is sent to Google.

Legal basis: your consent (Art. 6(1)(a) GDPR; Art. 5(3) of Directive 2002/58/EC as implemented by Art. 4a(1) of the Bulgarian Electronic Commerce Act).

2.5 Your cookie choice

When you make a choice in the cookie banner, we store a record of it on our server. This is how we prove what you agreed to. The record contains:

• a random identifier, also kept in the cookie_consent cookie;
• the categories you accepted or rejected;
• the date and time;
• the policy version.

It does not include your IP address.

Legal basis: our legal obligation to be able to demonstrate consent (Art. 6(1)(c) and Art. 7(1) GDPR).

Retention: 24 months after the choice expires or is changed.

2.6 Advertising

We do not currently show advertising on the Site. If we start, we will update this policy and ask for your consent before any advertising cookies are used.

2.7 Emails you send us

If you write to box@flyleaf.su, we use your email address and message to reply.

Legal basis: our legitimate interest in answering you (Art. 6(1)(f) GDPR).

Retention: as long as needed to handle your request, and no longer than 2 years after the last message.

3. Who receives your data

We use the following service providers. They act on our instructions as processors.

4. Cookies and similar technologies

"Cookies" here also covers similar technologies such as browser local storage.

Strictly necessary items are always active. The law allows them without consent because the Site cannot provide the service you request without them (Art. 4a(4), item 2 of the Bulgarian Electronic Commerce Act).

Analytics items are used only after you allow them in the cookie banner.

Changing your choice: you can change or withdraw your consent at any time through the Cookie settings link at the bottom of every page. Withdrawing consent does not affect processing done before the withdrawal.

The Widget uses no cookies or local storage and loads no analytics. It sends error reports as described in section 2.2.

You can also delete or block cookies in your browser settings. Blocking strictly necessary items may break parts of the Site.

5. Transfers outside the EEA

Sentry and Google. Data reaching Functional Software, Inc. (Sentry) and Google LLC in the USA is transferred under the European Commission's adequacy decision for the EU–US Data Privacy Framework (Implementing Decision (EU) 2023/1795). Both companies are certified under it.

Proton. Proton AG is in Switzerland, which the European Commission recognises as providing an adequate level of protection (Decision 2000/518/EC).

6. Your rights

Under the GDPR you have the right to:

• access your personal data and receive a copy;
• rectification of inaccurate data;
• erasure ("right to be forgotten");
• restriction of processing;
• data portability;
• object at any time to processing based on our legitimate interests, on grounds relating to your particular situation;
• withdraw consent at any time, with effect for the future, through Cookie settings.

How to exercise them: email box@flyleaf.su. We reply within one month. Where a request is complex, or we receive many requests, we may extend this by two further months and will tell you why within the first month.

Identifying your data: because we do not ask for your name or email, we may need information from you to find data relating to you, such as your IP address and the time of your visit.

Complaints: you have the right to lodge a complaint with a supervisory authority. In Bulgaria this is the Commission for Personal Data Protection (Комисия за защита на личните данни), 2 Prof. Tsvetan Lazarov Blvd., Sofia 1592, www.cpdp.bg. You may also contact the authority in your EU country of residence.

7. Other information

• You are not required to provide any personal data to use the Site.
• We do not use automated decision-making or profiling that produces legal or similarly significant effects for you.

8. Changes to this policy

We will update this policy when our processing changes. The version number and effective date at the top show the current version. If a change affects what you have consented to, the cookie banner will ask for your choice again.