How to use it
- Enter your home time zone and the destination. Your own zone is filled in for you, and you can swap the two.
- Set the date of travel, your usual bedtime and wake-up time, and how many hours a day you want to shift.
- Read the time difference and the number of days the shift takes. The table lists each night.
The rule
- Difference = destination offset − home offset on the travel date, reduced to the shorter way round the clock (up to 12 hours; at exactly 12 hours the tool shows east).
- Days to adjust = difference ÷ hours a day, rounded up.
- On night 1 the body still follows home time, so the expected bedtime is your usual bedtime plus the difference. Each further night the remaining difference shrinks by the chosen rate until it reaches zero.
Worked example
Flying from New York to Paris in November, Paris is 6 hours ahead. With a usual bedtime of 23:00 and a shift of one hour a day, the first night the body expects bed at 05:00 Paris time. It moves one hour closer each night, so after 6 days the expected bedtime is 23:00 again.
Remember
The schedule says nothing about light, caffeine, medication or sleep aids, and gives no health advice. It simply shows how a gradual shift of a fixed size would look in the local time.