Work out the NHS blood pressure band for a systolic and diastolic reading, and the reading that would move it into the next band.
Blood Pressure Category Checker keeps its state in memory and nowhere else. That is why it forgets everything on reload, and why it cannot leak anything.
The tool is a few kilobytes of JavaScript, not a service. That is why it can promise your data stays put and actually mean it.
You will find it under Health, alongside 18 other tools for the same sort of job.
Runs in this tab, so nothing you type is uploaded.
systolic: 128 diastolic: 82
Category: Pre-high blood pressure (borderline) Next band: A systolic reading of 140 mmHg or a diastolic reading of 90 mmHg would move this into the High blood pressure (hypertension) band.
Yes. It is JavaScript running in this tab, so once the page has loaded it needs nothing further from the network. Put the machine in flight mode and it carries on. Nothing you do here is sent anywhere, because there is nowhere for it to go.
No. Reload the page and it starts from nothing. There is no account, no saved state and no cookie holding your last session. That is a deliberate trade: it cannot lose your data because it never keeps any.
Timing comes from performance.now(), the high resolution clock the browser provides, rather than from setInterval, which drifts by a few milliseconds every tick and compounds over minutes. What can still shift things is the browser throttling a tab in the background, so leave it visible if the timing matters.
Where a sound makes sense, it is generated with the Web Audio API rather than loaded as a file, so there is nothing to download and nothing to block. Browsers refuse to start audio until you have interacted with the page, which is why the first press is what switches it on.
Yes. The controls are sized for touch and the layout collapses to one column on a narrow screen. Bear in mind that a phone locking its screen will suspend the page, and timing stops with it.