Privacy policy

Calculator input data

Amounts, body measurements, dimensions, and other calculator inputs are used for instant calculations in your current browser. They are not sent with page-view analytics or stored in the analytics database.

Data collected for page analytics

Optional first-party page, tool-use and performance measurement and Google Analytics stay off until you select Allow analytics. Rejecting does not affect calculator functionality. Google Analytics is excluded from admin pages and may process public page addresses, referrers, device information, interaction events and approximate location only after consent. A consented local analytics record may include:

Local page analytics do not store full User-Agent strings, names, email addresses, or calculator inputs, and our Google Analytics configuration does not intentionally send calculator form inputs. For traffic quality and abuse prevention, local IP collection is enabled by default: masked addresses and, when a strong server secret is configured, encrypted full addresses are retained for up to 30 days. Only allowlisted, signed-in administrators may explicitly reveal full addresses; normal responses show masked IPs. The IP is also used for offline geolocation and crawler-network verification on our server and is not sent to third parties by the local analytics system. Google processes Google Analytics data under its own privacy policy.

• Page path, interface language, page type, and calculator category;
• Referring website domain and UTM source, medium, and campaign values;
• Device category and whether traffic is classified as human, search crawler, or another automated client;
• Country and state or province information from a local offline IP database or explicitly configured trusted proxy headers, never city, coordinates, or precise location;
• Irreversibly hashed visitor and session identifiers used to aggregate visitor and session counts.

Cookies and sign-in sessions

The necessary toolify_privacy cookie records your allow/deny choice, policy version and timestamp for 180 days. No old preference is treated as current consent. Only after consent do local analytics identifiers and Google Analytics _ga cookies become eligible. Use Cookie & analytics settings at the bottom of any public page to change your choice. Withdrawal stops future optional measurement, clears accessible analytics cookies and requests removal of server-set identifiers; a page reload stops already-loaded Google code. It does not delete historical records automatically. Admin sign-in cookies remain separate. Advertising consent is not granted by this choice; ads remain disabled by default.

• clearcalc_visitor: a random visitor identifier lasting up to 400 days; only its hash is stored by the server.
• clearcalc_visit_session: a random visit-session identifier that expires after 30 minutes; only its hash is stored by the server.
• For allowlisted administrators only: verified email, GitHub username, display name, and avatar URL are kept in a signed login cookie for up to 7 days; temporary OAuth verification cookies last up to 10 minutes.

Theme preferences and offline storage

Your light, dark, or system theme preference is stored in this browser's local storage. On supported browsers, a service worker saves public page resources and a set of 50 English offline calculators in the browser cache. Visited public pages may also be cached, up to 100 pages. Calculator inputs and results are not serialized into this cache; admin pages, sign-in routes, and API responses are excluded.

These copies stay on your device and can remain after a tab closes. On a shared device, clear this site's browser data to remove theme preferences and offline copies. You can also remove the site's service worker through your browser's site settings or developer tools. Offline results still use the assumptions shown in each calculator; current website content requires a connection.

Purposes and retention

Analytics data is used to assess page usage, improve tools, understand search traffic, and protect the service. Detailed page views and anonymous tool events are retained for 400 days by default; deployments may shorten this period. Performance samples are retained for 90 days and expired records are pruned automatically. Tool events record input starts, successful results, validation errors, resets, and related-tool navigation, using only public tool identifiers rather than input or result values; Google Analytics may also receive these events with tool identifiers and language. Local performance measurement records LCP, INP, CLS, and TTFB values, public page paths, and device categories. These performance samples contain no IP addresses, full User-Agent strings, page-element contents, or form values, and are not separately forwarded to Google Analytics.

We do not sell personal information or use page analytics for third-party targeted advertising.

Your privacy controls

You can control first-party identifiers and future analytics records:

• DNT or GPC overrides an analytics allow choice. Without a current allow receipt, optional page, tool-event and performance APIs ignore measurements and do not create analytics identifiers. Operational server logs and identified crawler/security records are separate from optional visitor measurement;
• You can reject or withdraw through Cookie & analytics settings, delete cookies in browser settings, or use the Google Analytics Opt-out Browser Add-on. Clearing the preference cookie asks for a new choice rather than enabling analytics automatically;
• Allowlisted administrators can sign out at any time to clear the admin session.

Third parties and security

We use Google Analytics to produce aggregate reports about website use, and Google processes that data under its own privacy policy. Tool pages may also link to external sources such as CDC guidance, academic literature, or product information; those sites have their own privacy practices. GitHub OAuth is used only to authenticate allowlisted administrators; regular visitors do not need a GitHub account.

We use controls including HttpOnly and SameSite cookies, signed sessions, and hashed identifiers to reduce data risk, but no internet transmission or storage method is absolutely secure.

Policy changes and contact

We will update this page and its date when features, analytics scope, or applicable requirements change. For questions about data handling, or to request access to or deletion of relevant data, email the site maintainer at binjia70@gmail.com.