Cookies
The calculator stores nothing. Two things are saved on your device only because you asked for them — the language you choose, and your typical day if you tick the box. Advertising is the only other part that touches your device, and if you are in the EEA, the UK or Switzerland you will be asked about it before it does. What follows is exact rather than reassuring.
Working out your result
Nothing. Your bedtime, drinks and settings live in the page address, not on your device.
- Stored
- Nothing
- Set by
- —
- Retention
- —
Remembering your typical day
If you tick "remember this as my typical day", the drinks and settings you entered are saved in this browser so you do not retype them. Nothing is sent anywhere, and untick it to delete it immediately.
- Stored
- Only if you tick the box
- Set by
- This site only
- Retention
- Until you untick it or clear your browser data
Remembering your language
If you choose a language — from the switcher at the top of the page, or from the offer at the foot of it — that choice is saved in this browser so you are not asked again. It is one language code and nothing else, and it is not sent anywhere. Arriving on a translated page from a search result saves nothing; only your own click does.
- Stored
- Only the language you pick
- Set by
- This site only
- Retention
- Until you choose another language or clear your browser data
Analytics
Nothing on your device — no cookies and no storage of any kind. Visits are counted by a cookieless beacon our hosting provider adds at the edge, which reports the page address and timing, with no identifier that follows you between visits.
- Stored
- Nothing
- Set by
- Cloudflare, as our hosting provider
- Retention
- —
Advertising
If you consent, Google may use cookies and similar storage to choose ads and limit repetition. If you decline, ads are matched to the page you are reading instead. Either way its script saves one entry, google_auto_fc_cmp_setting, relating to the consent message itself — we neither set nor read it.
- Stored
- Your consent choice, and one setting
- Set by
- Google AdSense and its listed partners
- Retention
- Set by Google; your choice is kept so you are not asked repeatedly
If you decline, you still get ads — they are simply chosen from the page you are reading rather than from anything about you, and they earn less. Declining costs you nothing and costs us a little, which is the right way round.
You can change your answer at any time. The consent tool keeps a record of what you chose so it does not have to keep asking.
Last updated 2026-08-30. This is not legal advice.