Summary (TL;DR)
- DeckMath has no user accounts, so we never collect names, emails, addresses, or payment info.
- Calculator inputs are stored in your browser's localStorage and encoded in the share-link URL — never sent to our servers.
- We use Google Analytics 4 for aggregate, anonymous traffic statistics (no individual user tracking).
- We use Google AdSense when active. AdSense uses cookies for ad personalization.
- We do not sell, rent, or share data with third parties beyond what GA and AdSense require.
What information we collect
Information you provide
DeckMath has no signup, no login, and no contact forms that store submissions. The only way you provide information is by emailing us (e.g. [email protected]) — in which case we'll have whatever you put in the email until we delete it.
Information collected automatically
The following is collected automatically by standard web technologies:
- Server logs: IP address (anonymized), user-agent string, timestamps, and the URL path you requested. Retained 14 days for abuse prevention, then deleted.
- Google Analytics 4: aggregate page views, session duration, country (no city-level), browser, device class. GA4 anonymizes IP by default. We do not use User-ID.
- Google AdSense (when active): AdSense places cookies for ad personalization and frequency capping. You can opt out at google.com/settings/ads or via the per-page consent banner.
Information stored locally in your browser
Each calculator stores your last-used inputs in localStorage under a namespaced key (e.g. deckmath:deck-cost). The same data is also encoded in the share-link URL when you click "Copy link". This data never reaches our servers. To clear it, use your browser's "Clear site data" option.
Cookies
DeckMath itself does not set first-party cookies for tracking. The third-party cookies that may be set are:
- _ga, _gid (Google Analytics) — aggregate analytics, 2-year retention.
- __gads, __gpi (Google AdSense) — ad personalization and frequency capping.
- theme (DeckMath, localStorage not cookie) — your dark/light mode preference.
Children's privacy (COPPA)
DeckMath is not directed at children under 13. We do not knowingly collect personal information from children. If you believe a child has provided us with information, contact us and we'll remove it.
Your rights
Depending on where you live, you may have the right to:
- Access whatever personal data we hold about you (which is generally none).
- Request deletion of any data tied to your IP from our 14-day server logs.
- Opt out of Google Analytics via tools.google.com/dlpage/gaoptout.
- Opt out of personalized advertising at google.com/settings/ads.
California residents (CCPA), Virginia residents (VCDPA), and EU residents (GDPR) have additional rights — to exercise them, email [email protected].
Third-party services
When you click an outbound link to Home Depot, Lowe's, Trex, or another retailer, that destination's privacy policy applies. We may use affiliate tags in those links (Impact, CJ, Amazon Associates) when activated — disclosure is in the link itself when active.
Data security
DeckMath runs on a single VPS in Frankfurt with TLS 1.3, HSTS preload, and no public databases. Cloudflare sits in front for DDoS mitigation and edge caching. Since we don't collect personal data, the worst case for a server breach is leaked aggregate analytics.
Changes to this policy
We'll update the "Last updated" date at the top when this policy changes. Material changes will be flagged on the homepage for at least 30 days. Continued use after a change constitutes acceptance.
Contact
Questions about this policy? Email [email protected] or use the contact page.