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Jet lag calculator
See how many hours you will shift, whether you fly east or west, and simple tips to adjust.
General travel tips only. Not medical advice.
Frequently asked questions
How is the time shift calculated?
The tool compares the current UTC offsets of the two time zones on your device, including daylight saving, and shows the shorter way round the clock.
How long does jet lag last?
It varies by person and direction. A common rule of thumb is about one day of adjustment per hour of shift, but experiences differ.
Is this medical advice?
No. These are general travel tips only, not medical advice. Talk to a doctor or pharmacist if you have a health condition or take medicine on a schedule.
How to read the jet lag result
Pick your departure and arrival time zones and the calculator shows how many hours your body clock has to shift and in which direction. Crossing one or two zones barely registers for most people; from about three zones the shift starts to show as tiredness at the wrong time of day, poor sleep and low appetite. As a rule of thumb the body adjusts about one time zone per day, a little faster when travelling west, because staying up later is easier than falling asleep earlier.
What helps, in plain terms: set your watch to the destination time when you board, drink water and go easy on alcohol and coffee during the flight, and on arrival get daylight at the local morning if you flew east or the local late afternoon if you flew west, because light is the strongest signal for your body clock. Eat meals at local times from the first day. A short nap of twenty minutes is fine; a long afternoon sleep usually makes the first night worse. This is general travel advice, not medical advice: if you take time-sensitive medication such as insulin, ask your doctor how to shift the doses.