Light moves your clock
Bright light can move your body clock earlier or later depending on when your internal night occurs. Wrongly timed light may delay adjustment.
FREE, PRIVATE, SCIENCE-INFORMED
Cross time zones.
Cross time zones.
Keep your rhythm.
A clearer way to prepare for jet lag. Plan your sleep and light exposure, understand your body clock and arrive with a schedule that makes sense.
✓ No account✓ Your plans stay on your device✓ Works offline
☀☾
YOUR BODY CLOCK01:40Estimated biological time
DESTINATION08:40Local time
A day-by-day route back to feeling in sync
01 / CREATE YOUR PLAN
Tell us about your journey
No sign-in or uploads. All calculations run on this device.
02 / YOUR BODY CLOCK
Your adjustment plan
Enter your itinerary above to reveal your personalised schedule.
A calmer arrival starts here
Your timeline, light guidance and travel-day sleep suggestions will appear here once you create a plan.
Create a planDay-by-day schedule
All times displayed in the city/time zone indicated. Your biological clock is estimated and will vary.
03 / PICK UP WHERE YOU LEFT OFF
Saved journeys
Saved only in this browser, on this device. Export a copy before clearing browser data.
No journeys saved yet.
THE WHY BEHIND THE PLAN
Jet lag is a body clock problem
It's not just a lack of sleep. After a long flight, your internal day can be out of step with the sun.
Darkness matters too
Reducing light at certain times protects the shift you are trying to make. Sleep is important, but sleep timing alone does not fully explain jet lag.
Make room to adapt
Gradual schedule shifts before departure may help. Your chronotype, recent sleep, natural light and travel conditions will affect the outcome.
Transparent, research-informed, and independent
Our original planning model uses published circadian principles. It estimates body-clock timing from self-reported sleep, without measuring melatonin onset or core body temperature. It is not clinically validated, medical advice, or affiliated with other jet lag applications.
COMMON QUESTIONS
A few things to know
How do I reduce jet lag when travelling east?
Moving your sleep schedule earlier before travel may help. Timed light exposure is important, but the correct time depends on your estimated biological night. For large time changes, simply seeking light early in the morning can be counterproductive.
What about travelling west?
Westward trips usually call for delaying your internal clock. Evening light can help with some shifts, but personalised timing and the number of time zones crossed matter.
Can I enter flight numbers?
Yes. Add flight numbers to identify each leg. Live lookup is not yet available, so please enter and verify all flight times manually. Flight numbers and dates are stored only if you choose to save a journey.
How accurate are the recommendations?
They are approximations based on your usual sleep and the published principles of circadian phase shifting. They cannot measure your internal clock or predict precisely when you will recover. Illness, sleep loss, light exposure and individual differences affect results.
Do I need melatonin or sleeping tablets?
No. JetRhythm does not prescribe medication or generate individual melatonin doses. Ask a qualified clinician or pharmacist before considering it, particularly if you take medicines or have a medical condition.
Do you send my itinerary to a server?
No. The calculator runs locally. When you explicitly save a plan, it goes into your browser's storage. Normal website and third-party asset requests may still be visible to the hosting and asset providers; see the privacy information below.
YOUR DEVICE, YOUR DATA
Private by design
JetRhythm requires no account. Trip calculations happen in your browser. Saved journeys are kept locally and can be exported or deleted at any time. No tracking or advertising cookies are set by JetRhythm.
What leaves your browser?
The online version requests page files from hosting and shared Mightora assets from GitHub/jsDelivr. These providers may process standard connection information. No itinerary data is included in those requests.
Full privacy and local storage notice ↗ · Network transparency ↗
