Privacy Policy

This Privacy Policy explains how CalkHub ("we," "us," or "our") collects, uses, and protects information when you visit our website. We are committed to protecting your privacy and being transparent about our data practices.

By using CalkHub, you agree to the collection and use of information as described in this policy. We update this policy periodically — the date at the top of this page reflects the most recent revision.

We collect minimal information to provide a reliable experience:

• Server Logs: Standard access logs (IP address, browser type, pages visited) retained for up to 90 days for security and debugging. Logs are not linked to personal identifiers.
• Contact Form Data: If you contact us, we store your name, email, subject, and message to respond to your inquiry. This data is never sold or shared with third parties.
• Analytics Data: We use a lightweight self-hosted analytics system to count page views and understand site usage. No personally identifiable information is stored and no data is shared with third parties.

All calculations on CalkHub run entirely in your web browser. Input values you enter into calculators are never transmitted to our servers, never stored, and never analysed. Your calculation data stays on your device at all times.

CalkHub uses the following categories of cookies:

• Strictly Necessary: Required for core site functionality (e.g. security, session management). These cannot be disabled.
• Analytics: Our self-hosted analytics system uses first-party cookies (_ch_vid, _ch_sid) to count unique visitors and sessions. No data is shared with third parties.
• Advertising Cookies (if enabled in the future): If Google AdSense is ever activated, Google may place advertising cookies on your device. You will be notified via a consent banner before this occurs. See our Cookie Policy for full details.

You can manage cookies via your browser settings. Blocking all cookies may impair some site features.

CalkHub is currently ad-free. We may use Google AdSense in the future to help keep the site free for everyone. If advertising is ever enabled:

• You will be notified via a cookie consent banner before any advertising cookies are placed.
• Google AdSense is provided by Google LLC (1600 Amphitheatre Parkway, Mountain View, CA 94043, USA).
• Google may use cookies (including the DoubleClick DART cookie) to serve interest-based ads based on your browsing history.
• You can opt out at any time via Google's Ads Settings or the NAI opt-out page.

We currently use a lightweight self-hosted analytics system that records page views, session metadata, device type, browser, and country. This system uses only first-party cookies, stores no personally identifiable information, and shares no data with third parties. Raw data is automatically purged after 60 days.

CalkHub may interact with the following third-party services, each with its own privacy policy:

• Google AdSense (if enabled in the future) — Advertising. Privacy Policy | Opt-out
• Google Analytics (if enabled) — Anonymised usage analytics. Privacy Policy

We do not sell, rent, or trade your personally identifiable information to any third party.

We implement appropriate technical and organisational measures to protect your information against unauthorised access, alteration, disclosure, or destruction. Passwords are hashed using Argon2id. All connections to CalkHub are secured via HTTPS/TLS.

No method of transmission over the internet or electronic storage is 100% secure. While we strive to protect your data, we cannot guarantee absolute security.

Contact form messages are retained for up to 24 months to handle follow-up correspondence. Server logs are retained for up to 90 days. You may request deletion of your contact data at any time by emailing us.

CalkHub is not directed at children under the age of 13. We do not knowingly collect personal information from children under 13. If you are a parent or guardian and believe your child has submitted personal information, please contact us and we will promptly delete such information.

Depending on your location you may have the right to:

• Access — request a copy of personal data we hold about you.
• Rectification — request correction of inaccurate data.
• Erasure — request deletion of your personal data.
• Restriction — request that we restrict processing of your data.
• Portability — receive your data in a structured, machine-readable format.
• Objection — object to processing based on legitimate interests.

To exercise any of these rights, contact us via our Contact page. We will respond within 30 days.

We may update this Privacy Policy periodically to reflect changes in our practices or for legal, regulatory, or operational reasons. We will update the "Last updated" date at the top of this page. Your continued use of CalkHub after changes constitutes acceptance of the updated policy.

If you have questions, concerns, or requests regarding this Privacy Policy, please contact us via our Contact page. We aim to respond to all privacy enquiries within 5 business days.