Privacy policy
The calculator runs on your device. Your route, your flight times and your sleep window are never transmitted, never stored and never shared.
Effective 26 September 2026.
Summary
| Flight route and times | Processed in your browser, never transmitted |
|---|---|
| Sleep window | Processed in your browser, never transmitted |
| Account data | None collected, no account exists |
| Payment data | None collected, the tool is free |
| Cookies set by this site | Analytics only, no advertising cookies |
| Browser storage used | One entry recording your light or dark theme choice |
| Data sold or shared | None |
What you enter into the calculator
Everything you type into the calculator stays on your device. The airport list is a static file your browser downloads once, and the schedule is computed in your browser from that file. No request carries your route, your dates or your sleep hours anywhere.
Closing the tab discards the plan. Nothing persists unless you print it or copy it yourself.
Browser storage
The site writes a single entry to your browser local storage to remember whether you chose the light or the dark theme. That entry contains the word light or the word dark and nothing else. It never leaves your browser. Clearing your site data removes it.
This site sets no cookies and displays no cookie banner, because it needs neither.
Server logs
The site is served as static files by a hosting provider. Like any web host, that provider records standard request logs, which may include your IP address, the page requested, the time of the request and your browser user agent. Those logs exist to keep the service running and secure. They contain no information you entered into the calculator.
Analytics
The site uses Microsoft Clarity to understand which pages are read and where the interface causes difficulty. Clarity records aggregated usage signals such as page views, clicks, scroll depth and general device and location information, and it reconstructs anonymised session replays from those signals.
Clarity never receives the contents of the calculator fields. Input values are masked by default in Clarity replays, and the calculator transmits nothing to any server in the first place. Microsoft processes this data as described in the Microsoft privacy statement, and you can opt out through your browser do not track or global privacy control setting where Clarity honours it.
Google Search Console is connected to this site. It reports how pages perform in Google Search results using aggregate data Google already holds. It places no script on the site and receives nothing from your visit.
Third parties
Web fonts are served from the same origin as the site, so no font request reaches a third party. The airport dataset is compiled at build time from OurAirports, which releases its data into the public domain, and is served from this site rather than fetched from elsewhere at runtime.
Your rights
Because the site holds no personal data about you, there is nothing to export, correct or delete on request. If you believe otherwise, write to hello@jet-lag-calculator.com and we will look into it.
Children
The site is a general information tool and is not directed at children under 13. It collects no personal data from anyone, including children.
Changes to this policy
Material changes to this policy are published on this page with a new effective date. Continuing to use the site after a change means accepting the updated policy.