Privacy Policy

CalcCircuit ("we", "our", "us") respects your privacy. This policy explains what data we collect, how we use it, and what choices you have. It is written in plain English and designed to comply with the EU General Data Protection Regulation (GDPR), the California Consumer Privacy Act (CCPA/CPRA), and Google's AdSense program policies.

1. Data we collect

We collect three categories of data:

• Data you provide directly. Email address when you sign in or subscribe to the newsletter. Optional note text when you save a calculation.
• Data collected automatically. Anonymous usage analytics (pages viewed, button clicks, calculation types), aggregated traffic source (referrer), device type, browser, country (from IP, not stored in full), and timestamps.
• Data from third parties. Google AdSense and Google Analytics 4 may set cookies and collect information as described in their own policies.

We do not collect your financial inputs or calculation results. All calculations run in your browser; only the result text and tool slug are optionally sent to our analytics endpoint for usage statistics.

2. How we use your data

• To provide, maintain, and improve our calculators and tools.
• To remember your preferences (theme, saved calculations, consent choices).
• To send you newsletters if you have explicitly subscribed (you can unsubscribe in one click from any email).
• To generate anonymous usage statistics and detect abuse.
• To display ads through Google AdSense (see Section 5).
• To respond to legal requests when required by law.

3. Cookies and similar technologies

A cookie is a small text file stored in your browser. We use the following cookies:

• Essential cookies. Theme preference (theme), consent record (calccircuit_cookie_consent), saved calculations (calccircuit_saved_v2). These cannot be disabled because the site does not work without them.
• Analytics cookies. Set by Google Analytics 4 (_ga, _ga_*) if you accept analytics in the consent banner.
• Advertising cookies. Set by Google AdSense (typically __gads, __gpi, IDE) if you accept personalized ads in the consent banner. If you reject, we set requestNonPersonalizedAds=1 so AdSense shows non-personalized ads only.

You can change or withdraw your consent at any time by clearing the calccircuit_cookie_consent localStorage key and reloading the page.

4. Local storage and offline data

We also use your browser's localStorage to remember your saved calculations and theme preference. This data never leaves your device unless you explicitly choose to sync it to your account via our cloud sync feature. You can clear it at any time from your browser settings or via the "Clear All" button on the Saved Calculations page.

5. Third-party services

To run this site we rely on the following third-party services. Each has its own privacy policy and may collect data as described there.

• Google AdSense — displays advertisements on this site. AdSense uses cookies to serve ads based on your prior visits to this site or other sites. Google's use of advertising cookies enables it and its partners to serve ads based on visits to this and/or other sites. You can opt out of personalized advertising by visiting Google Ads Settings.
• Google Analytics 4 — measures aggregated traffic and engagement. You can opt out by installing the Google Analytics Opt-out Browser Add-on or by rejecting analytics in the consent banner.
• Cloudflare Pages & D1 — our hosting and database provider. Cloudflare's privacy policy is available at cloudflare.com/privacypolicy.

6. Your rights (GDPR / CCPA)

Depending on where you live, you have some or all of the following rights:

• Access — request a copy of the personal data we hold about you.
• Rectification — ask us to correct inaccurate data.
• Erasure — ask us to delete your data ("right to be forgotten").
• Restriction — ask us to limit how we process your data.
• Portability — receive your data in a machine-readable format.
• Objection — object to processing based on legitimate interest.
• Withdraw consent — at any time, for processing based on consent.
• Lodge a complaint — with your local data protection authority.

To exercise any of these rights, email [email protected]. We respond within 30 days.

7. Children's privacy

Our service is not directed to children under 13 (or under 16 in the EEA). We do not knowingly collect personal data from children. If you believe a child has provided us with personal data, contact us and we will delete it promptly.

8. Data retention

• Analytics events are retained for 90 days, then aggregated or deleted.
• Newsletter subscriptions are kept until you unsubscribe.
• Account & saved calculations are kept while your account is active. We delete inactive accounts after 24 months of no login.
• Server logs (Cloudflare) are retained according to Cloudflare's standard policies.

9. International data transfers

Our servers are located in the United States (Cloudflare edge network). By using the site, you understand your data may be transferred to and processed in the US, which may have different data protection rules than your home country. We use standard contractual clauses with our processors where required.

10. Security

We use HTTPS everywhere, hashed session tokens, rate-limited APIs, and Cloudflare's edge security to protect your data. No method of transmission over the internet is 100% secure, but we work hard to keep your data safe.

11. Changes to this policy

We may update this policy from time to time. The "Last updated" date at the top will always reflect the latest revision. Material changes will be announced via the cookie banner and (for active subscribers) by email.

12. Contact

For privacy questions, data access requests, or to lodge a complaint:

• Email: [email protected]
• General: Contact form
• Postal: CalcCircuit, 548 Market St, San Francisco, CA 94104, USA

This policy is also available as a plain text version for archival purposes.