Jet Lag Calculator
Estimate how much jet lag to expect when flying between any two timezones — and get tips to recover faster.
Select your departure and arrival timezones
⚠️ Estimates are based on general travel guidance and the current time difference between your selected timezones. Your experience may vary based on age, sleep habits, and flight direction. Always consult a health professional if you have concerns about long-distance travel.
Eastward Travel
Time moves ahead — your body clock lags behind. Typically harder to adjust to and often more disruptive.
Westward Travel
Time moves back — you get extra hours. Usually easier to adjust to, though you may struggle to stay awake.
Roughly 1 Day Per Hour
A common rule of thumb: allow about one day of adjustment for each hour of time difference.
Frequently Asked Questions
How is jet lag calculated?
Jet lag is driven by the time difference between your departure and arrival timezones. This tool reads the live UTC offset of each timezone from your browser's built-in timezone database, computes the shortest time gap, and translates it into a severity estimate using widely cited recovery guidance.
Why is eastward travel worse than westward?
Flying east shifts your body clock forward, so you're told to go to bed and wake up earlier than usual. Most people find it harder to fall asleep early than to stay awake later, which is why eastward trips tend to produce more disruptive jet lag. Flying west "gains" hours, which is closer to our natural tendency to sleep later.
How long does it take to recover from jet lag?
A common rule of thumb is that the body adjusts at a rate of about one day per hour of time difference. A 6-hour difference typically takes roughly 4–6 days to fully reset. Age, sleep quality, meal timing, and sunlight exposure all affect how quickly you adapt.
What can I do to reduce jet lag?
Start adjusting your sleep schedule a few days before you fly, get bright natural light in the morning at your destination, stay hydrated, and avoid alcohol and caffeine close to bedtime. Short naps (under 30 minutes) can help, and a melatonin supplement — with your doctor's approval — may ease the transition.
Does daylight saving time affect the result?
Yes. This tool uses the current, live UTC offset for each timezone at the moment you calculate, so daylight saving time is automatically taken into account. If either region changes its clocks between now and your trip, the difference may shift by an hour.