The short version
No account is needed. Calculations run locally, and history stays in page memory unless you choose to save up to 8 entries on this device. Google Analytics (aggregate, anonymous traffic measurement) and a third-party advertising banner are both off by default and load only after you accept the cookie banner. Until then, neither makes any external request or sets any cookie.
What the application does not do
- No server-side calculation. Your numbers are processed by your own browser; the calculator does not submit them anywhere to be computed, and it does not send your inputs or saved history to Google Analytics or the advertising provider.
- No individual profiling by this site. The site itself builds no account profile and does not attempt to identify you. It does load Google Analytics for aggregate traffic measurement (see Google Analytics) and an advertising banner (see Third-party advertising); both are described plainly below rather than hidden.
- No accounts or logins. There is nothing to sign up for, and the calculator creates no account profile.
- No email or contact collection. There is no newsletter, no contact form and no feedback endpoint in this build.
Google Analytics
This site loads Google Analytics 4 (measurement ID G-LTSS5G3Z8Q) from www.googletagmanager.com to understand aggregate, anonymous usage — for example how many people open a page and which pages are visited. Analytics runs only to measure traffic; your calculation inputs, results and saved history are never sent to it.
Google Analytics sets its own first-party cookies in your browser (typically named _ga and _ga_G-LTSS5G3Z8Q) and may collect standard information such as an approximate location derived from your IP address, device and browser type, and the pages you view. This data is processed by Google; see Google's own privacy and Analytics terms for how it is handled. IP addresses are not stored by Google Analytics 4 in its reports.
Consent comes first. This build uses Google Consent Mode v2 with analytics_storage set to denied by default, so no analytics cookies are written and no measurement is sent until you act. The first time you visit, a banner asks you to Accept or Decline. Analytics runs only after you accept; declining, or simply ignoring the banner, leaves analytics off. Your choice is remembered on this device (a small lcm-consent value in localStorage) so the banner does not reappear.
You can also opt out at the browser level: block the domain with a content blocker, decline it through your browser's privacy controls, or install Google's Analytics opt-out add-on. To change a previous choice, clear this site's data and reload to see the banner again. Blocking or declining analytics does not affect the calculator, which works the same either way.
Note for operators. The consent banner defaults to denying analytics, which suits EU/UK GDPR and ePrivacy expectations for a single third-party measurement tool. If you add further tracking or advertising personalisation, review whether a fuller consent-management platform is required. This page describes the integration; it is not a legal compliance certification.
Third-party advertising
A 728 × 90 banner above the footer loads an advertising script from www.highrevenueformat.com. This banner is gated behind the same cookie consent as analytics: it stays hidden and makes no request until you accept, and declining (or ignoring the banner) leaves it unloaded. Once loaded, the provider may request additional resources from other domains. These requests expose network and browser information to those services, which may use cookies, storage, device signals or measurement. Their behaviour is separate from the calculator's local settings and is not covered by a promise of no tracking.
The banner loads in a separate, non-sandboxed frame to support the provider's script. This frame keeps the banner's script loading separate from calculator startup, but it is not a security boundary: the third-party script can access the parent page and same-origin storage. The integration does not explicitly send your inputs or saved history to the provider, but you should not enter sensitive information on an advertising-supported page. Cross-origin requests use an origin-only referrer policy. Ad blockers, browser privacy settings, network failures and provider availability can prevent a banner from appearing; the calculator can still be used.
Because the banner only loads after you accept the cookie consent, no advertising request is made without consent. The site operator should still review the provider's actual privacy practices and audience suitability before deployment, especially where children may use the site. This page is a description of the integration, not a legal compliance certification.
What is stored on your device
The calculator can write a few small values to your browser's localStorage, all under your control: your colour theme, optionally your saved history, and your cookie-consent choice. Google Analytics (only after you accept) and advertising services set their own separate cookies or storage. Everything is summarised in the table below.
| Item | When it is written | How much | How to remove it |
|---|---|---|---|
| Colour theme preference (light or dark) | When you use the theme toggle in the header | A single short value | Clear site data to remove the saved preference; toggling changes it but does not delete it |
| Saved calculation history | Only if you tick the opt-in save history on this device checkbox | At most 8 entries | Untick the checkbox and clear the history, or clear site data |
Cookie-consent choice (lcm-consent) | When you click Accept or Decline on the cookie banner | A single short value (granted or denied) | Clear site data; reloading then shows the banner again |
Google Analytics cookies (_ga, _ga_G-LTSS5G3Z8Q) | Only after you accept analytics on the cookie banner | Two cookies, expiring after up to about two years | Decline the banner, block the analytics domain, use the opt-out add-on, or clear site data |
On a hosted site, localStorage belongs to the site's origin (scheme, hostname and port), not just this page. Other pages and scripts on that same origin can access it; pages on a different origin cannot normally do so. Local-file storage behavior varies by browser. This application does not transmit these values or combine them with other data. Clearing the browser's site data removes them.
By default, calculation history is kept in the memory of the current session and disappears when the tab is closed or reloaded. The opt-in checkbox exists precisely so that a small, bounded amount of convenience does not become permanent storage without your knowledge.
Hosting and access logs
This privacy page describes the application, which is a folder of static files. If the pages are served from a website, whoever hosts them — a school, a company, a shared host, a cloud platform — may keep its own standard access logs, typically including the requested page, the time of the request, an IP address and browser details. Those logs are created and controlled by the host, not by the application, and this build cannot describe them precisely because it does not provide the hosting.
Two practical consequences:
- If you open local files, no hosting request is needed for the calculator itself. The advertisement can still make external requests when you are online.
- If someone else hosts the files, questions about those logs should be directed to that host. Anyone deploying this site is encouraged to add their own specific hosting disclosure, since a generic statement would not be accurate for every platform.
External links
The About & sources page links to other websites so that claims can be checked. Following a link connects your browser to that site, which can receive your IP address and browser details and applies its own privacy policy. The source links in this build use rel="noreferrer" to suppress the referring-page header. This does not make a visit anonymous.
Students and general users
The calculator does not ask for an account or age and does not create user profiles. This does not mean every connection is anonymous: hosting and third-party advertising can receive network or device information. Schools, parents and site operators should assess advertising suitability before using the hosted site with students. Shared URL fragments can reach browser history, and downloaded files remain on your device.
What this page does not claim
This page describes what the code does; it is written plainly rather than as a legal certification. It does not assert blanket compliance with any particular regulation or framework, because compliance depends on who deploys the site, where, and for whom — factors outside this build. It also does not claim that the site is immune to the normal risks of using any web browser or web host. Where a hosting provider's practices matter, that provider is the correct source of information.
Changes to this page
If the storage behaviour of the application changes, this page should change with it, because a privacy description that lags behind the code is worse than none. This description was updated on 21 September 2026 to include third-party banner advertising, and on 23 September 2026 to include Google Analytics 4 traffic measurement. Related information appears on the accessibility, terms and about pages.