Privacy

The calculator

Everything the calculator does happens in your browser using JavaScript on the page. The wake-up time, bedtime, cycle length, age band and time format you choose are held in memory while the page is open and are discarded when you close the tab.

None of it is transmitted to a server, stored in a cookie, saved to local storage, or associated with you. There is no account, no login, and no way for this site to know what times you entered.

The calculator does read one further thing: your device's clock, so it can tell you that a suggested bedtime is “in 3 hours” or that it went past an hour ago. That is read locally and never sent anywhere. It is worth mentioning because the obvious alternative, looking up your time zone from your IP address, would mean calling a third-party service, and this site does not call any.

The Android app

The app on Google Play is this website packaged for Android. Every page, font and script ships inside the download, so it runs with no connection at all and does not fetch anything from this server while you use it. There is no account and no sync.

It adds one feature the website cannot offer: a bedtime reminder. If you set one, the app asks Android to raise a notification at that time. The reminder is scheduled by your phone's own alarm service: it does not involve a server, and no push service is used, which means your bedtime is never transmitted anywhere to make the notification arrive.

Making that work requires the app to remember three things between launches: the time you chose, how many minutes before it you want warning, and whether it should repeat nightly. Those are written to local storage on the device. They are not sent anywhere, not backed up to us, and are erased when you uninstall the app or clear its storage. Cancelling the reminder removes the scheduled notification.

The app requests four Android permissions: to post notifications (the reminder itself), to set an exact alarm, to restore a pending reminder after a reboot, and network access, which is used only when you tap an external source link in an article and your browser opens it.

The exact-alarm permission is worth explaining, because it is the one Android treats as sensitive. An ordinary alarm can be postponed by the system to save battery: in testing, one was given an hour-wide delivery window and had still not arrived seven minutes after it was due. A reminder that turns up at an unpredictable point in the following hour is not a reminder, so the app asks for the exact kind. It is used for nothing else, it schedules your bedtime reminder and nothing more.

Cookies

MySleepMate sets no cookies of its own. Nothing on this site identifies you, remembers you between visits, or follows you elsewhere on our account.

Google AdSense does set cookies. Since 30 August 2026 this site carries advertising served by Google. Google and its advertising partners use cookies and similar technologies to serve ads, to limit how often you see the same ad, and to measure whether an ad worked. Depending on your settings, some of those ads may be personalised using data Google already holds about you from elsewhere. That is Google collecting and using data, not this site, and it happens through their code rather than ours.

You can control this directly with Google, independently of anything here:

• Turn off personalised advertising at Google My Ad Center.
• Read what Google does with data from sites that use its products at policies.google.com/technologies/partner-sites.
• Opt out of third-party vendor cookies for ad personalisation at aboutads.info/choices.

Blocking cookies in your browser also works, and the calculator will still function normally without them, because it never used them.

If you are in the UK, EEA or Switzerland

You will see a consent message the first time you visit, asking what Google may do with your data. It is served by Google's own certified consent management platform, which is the mechanism Google requires publishers to use in those regions, and your answer is recorded and respected by the advertising system rather than by us.

If you decline personalisation you will still see advertising, because the ads are what pay for the site, but it will be non-personalised. You can change your answer later through the same message or at Google My Ad Center.

Third parties

Two companies, across six domains. This list was produced by loading the site in a browser and recording every outside request, rather than by reading our own source code, which is how the second one was missed.

Contacting any of these means the company receives your IP address, your user agent and the address of the page you are reading, because that is what making a request involves. Google may additionally set cookies; Cloudflare does not.

Everything else remains first-party. Fonts, scripts, icons and images are served from mysleepmate.com itself. There is no tag manager, no session recording, no social embeds and no trackers beyond those six.

The ordinary exception also applies: your web host processes standard server request logs, as every web server does.

Analytics and advertising

There is analytics, and this page said there was not. Cloudflare Web Analytics runs on every page. It counts page views, referrers, countries and browsers, and reports them to me in aggregate.

Two things in its favour, both of which I checked rather than took on trust. It sets no cookies, and it writes nothing to local storage: I loaded the site and inspected both, and they were empty. And it does not build a profile of you or follow you to other sites. Of the analytics options available it is among the least invasive, which is presumably why Cloudflare turns it on by default.

Which is exactly how I missed it. It is injected by Cloudflare at the edge, so it does not appear anywhere in this site's source code and does not show up if you fetch the page with a command-line tool. It only appears when a real browser asks for a real page. I had been reading our own files and concluding there was no analytics, which was a statement about our repository rather than about your visit.

There is still no tag manager and no session recording. Nobody is watching your cursor or replaying your session.

There is advertising. Google AdSense has been on every page since 30 August 2026, and it is how the site pays for itself. What Google collects through it is described under cookies and third parties above.

Contacting us

If you email, the email exists in the inbox it was sent to, along with whatever you chose to put in it. It is not added to a mailing list, because there is no mailing list.

Changes to this page

Material changes to what this site collects will be reflected here. This page was last reviewed on 31 August 2026.