Privacy

What happens to a reading you type in

The calculator runs entirely on your device. The two numbers exist in your browser’s memory while the page is open and are gone when you close the tab. They are not put in the web address, not stored in a cookie, not written to a log, and not included in any error report.

If you use the log, your saved readings are stored in this browser on this device only, using your browser’s own local storage. They are never sent to us and we cannot see them. Clearing your browser data, using a different device, or private browsing will lose them.

Don’t take our word for it

A privacy policy is a claim. Here are the two mechanisms that make this one checkable.

One. This site sends a Content-Security-Policy header with form-action 'none', which instructs your browser to block form submission to anywhere, and a connect-src list naming only Google’s analytics endpoints. Your browser will refuse to send a network request to any other destination, whether or not our code tries to make one. Open your developer tools, watch the network tab, and enter a reading: the only requests are the analytics ones described below, and none of them carries your numbers.

Two. Every change to this site is checked automatically for outbound calls in any code that touches a reading, and for any third-party tag added inside those files. A change that introduces one fails before it can be published.

Being straight with you about the change. Until 5 August 2026 this site blocked all outbound requests, and this page said so. Adding analytics required opening a narrow exception, and that is a genuinely weaker guarantee than the one it replaced. It is described here rather than quietly dropped.

What we do not collect

• No account, sign-in, name, date of birth, phone number or email address. There is no field anywhere on this site that asks for any of them.
• No blood-pressure readings, ever, in any form. They are not put in the web address, the page title or anything sent to the analytics service.
• No advertising, no session recording, no A/B testing tool and no chat widget — on any page.
• No fonts or images loaded from anyone else’s server. The only external script is Google Analytics, described below.

Analytics

This site uses Google Analytics 4 to count visits and see which pages people use. It runs on every page, including the calculator and the log.

What it receives: the address of the page you are on, the page title, the address of the page you arrived from, your approximate location from your IP address, and your device and browser type. It sets cookies to recognise a returning browser.

What it does not receive: your blood-pressure readings. No reading is ever placed in a web address, a page title or a page name, and no analytics event on this site carries a reading value — so there is nothing containing your numbers in what is sent. The readings saved in your log are held in your browser’s local storage, which the analytics script does not read.

What we are not claiming: that it is impossible for it to see a reading. Any script running on a page can read what is on that page. What we can tell you is what this one is configured to send, which is the list above. If you would rather it did not run at all, a tracker blocker or your browser’s “do not track” extensions will stop it, and the calculator and log work exactly the same without it.

Cookies

One of ours, and only if you use the light/dark toggle. It holds the word “light” or “dark” so the page does not flash the wrong colours when you come back. It contains nothing else, and no reading value can reach it.

Google Analytics also sets its own cookies to recognise a returning browser and group page views into a visit. They hold a randomly generated identifier, not anything you have typed. Clearing your cookies removes them.

No devices, no health apps

bpmeter will not connect to a Bluetooth cuff, a smartwatch, Apple Health, Google Fit, Health Connect or any other health service, in this version or a later one. Readings are typed in by hand and that is the only way in. The site also tells your browser to make Bluetooth unavailable to it entirely, so the capability is absent rather than merely unused.

If this ever changes

If any further third-party service is ever added to a page on this site, this page will be updated in the same change that adds it — as it was on 5 August 2026 when analytics was added. A privacy policy that has fallen behind the code is worse than none, so the update is part of the change rather than a follow-up to it.