Calculate jet lag severity and recovery time when crossing time zones.
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Time difference
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Recovery
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Direction
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About This Jet Lag Calculator
This free jet lag calculator estimates your recovery time after long-haul flights and provides a personalised schedule for sleep, meals and light exposure to help you adjust faster.
Jet lag occurs when your body's internal clock (circadian rhythm) is out of sync with the local time zone. The more time zones you cross, the more severe jet lag tends to be.
How to Beat Jet Lag
Key strategies: adjust your sleep schedule 2-3 days before travel, avoid alcohol on the flight, stay hydrated, get natural sunlight at your destination at the right times, and consider melatonin (widely used for jet lag — discuss with your doctor). Eastward travel typically causes worse jet lag than westward.
Frequently Asked Questions
How long does jet lag last?+
Typically 1 day per time zone crossed, though this varies. Westward travel usually resolves in 2-3 days; eastward travel may take 4-7 days.
Is jet lag worse going east or west?+
Eastward travel (against your body clock direction) tends to cause more severe and longer-lasting jet lag than westward travel.
Does melatonin help with jet lag?+
Research supports melatonin as effective for jet lag. Timing is critical — take it at your destination's bedtime, not at your departure timezone bedtime. Discuss with your doctor.
Should I sleep on the plane?+
This depends on your arrival time. If arriving in the morning, try to stay awake on the plane. If arriving at night, sleep on the plane to align with destination time.
How can I reduce jet lag before I fly?+
Gradually shift your sleep schedule 2-3 days before departure (earlier for westward, later for eastward). Avoid heavy meals and alcohol before and during the flight.