How to use the jet lag sleep schedule planner
- Choose the departure city, the destination city and your departure date.
- Enter your usual bedtime and wake time. Untick the box if you do not want to adjust before departure.
- You get the time difference, the direction to adjust, a rough number of days to adapt, and a table of recommended bedtimes and wake times for the days before and after the trip.
How it is calculated
First the difference in offset from Coordinated Universal Time (UTC) between the two cities on your departure date gives the clock difference. If it exceeds 12 hours it is converted to the opposite direction so that it falls between −12 and +12 hours; for example −13 hours is treated as +11 hours. A positive value means eastward travel (shift your clock earlier) and a negative value means westward travel (shift your clock later), which sets the direction to adjust.
Pre-departure adjustment shifts bedtime and wake time toward the destination by 1 hour per day for up to 3 days. After arrival the body clock is assumed to catch up by 1 hour per day eastward and 1.5 hours per day westward, and the remaining difference is divided by that rate to get the days needed. For each day the tool computes the local time you would feel sleepy while your body clock is still on the origin time, and the recommended bedtime is set up to 2 hours closer to the destination than that. The length from bedtime to wake time is your usual sleep duration.
General reference tips
- Light is known to be a major factor that moves the body clock. The general advice is to use local morning sunlight when traveling east and local evening light when traveling west.
- Keep naps to 20-30 minutes and avoid them late in the afternoon.
- Caffeine and alcohol can disturb sleep, so cut back from the late local afternoon.
- If you have an important event right after arrival, arriving a day earlier is another option.
Things to know
This calculator is a reference plan built on common rules of thumb and is not medical advice. Adaptation speed differs a lot between people, and flight length, connections and arrival time change how you actually feel. A difference under 2 hours is easy for most people to handle without a plan. Sleep aids, melatonin and other supplements are deliberately not covered; if you are thinking about using them, talk to a doctor or pharmacist. If you work night shifts, have a sleep disorder, are pregnant or have another special situation, follow professional guidance first.
FAQ
How many days does it take to adjust?
There is no fixed number, but a common rule of thumb is about 1 hour per day eastward and about 1.5 hours per day westward. So an 8-hour difference may take about 8 days eastward and 5 to 6 days westward. Age, usual sleep habits and how you get light change this a lot.
Why is traveling east harder?
The human body clock runs slightly longer than 24 hours, so it is said to shift later fairly easily but to move earlier with more difficulty. Eastward trips require shifting earlier, so many people find them harder.
Is daylight saving time taken into account?
Yes. The real difference between the two cities on the departure date is read from the time zone data in your browser, so daylight saving time on that date is included. The arrival date is assumed to be the same as the departure date.
Privacy
The cities, dates and sleep times you enter are never sent to a server and are calculated only inside your browser.