Jet Lag Calculator
Get a simple light-exposure and sleep adjustment plan based on how many time zones you're crossing and which direction.
Estimated adjustment time
~6 days
• Get sunlight in the morning after eastward flights, and in the evening after westward flights.
• Start shifting your sleep schedule 1–2 days before you fly, in the direction of your destination.
• Stay hydrated and avoid alcohol during the flight — dehydration makes jet lag worse.
• Adopt the local meal and sleep schedule as soon as you land, even if you're not tired.
Rule of thumb: eastward travel is roughly 1 day of adjustment per time zone; westward is a bit faster, around ⅔ day per zone.
How the Jet Lag Calculator works
Enter how many time zones you're crossing and your direction of travel. The calculator estimates how many days it will likely take to adjust, plus practical tips to speed up the process.
Frequently asked questions
Why does direction matter?
Most people adjust faster to westward travel (which lengthens the day) than eastward travel (which shortens it), since it's generally easier to stay up later than to fall asleep earlier.
How many time zones am I crossing?
Check the time difference between your departure and arrival cities — that's the number of time zones crossed.