🛫Jet Lag Calculator

About this tool

Choose your departure and destination UTC offsets. The tool shows the shift in hours and its direction, a typical adjustment time, and tips for before your flight and after you arrive.

Beating jet lag

Jet lag is the mismatch between your body clock and local time after flying across time zones. It brings poor sleep, daytime tiredness, low concentration and stomach upsets. A rule of thumb is about one day to adjust for each time zone crossed travelling east, and somewhat less travelling west. Westward trips are usually easier because the body clock naturally runs slightly longer than 24 hours and finds it easier to stay up later than to fall asleep earlier. Light is the strongest signal for resetting the clock. Morning light pulls it earlier, which helps after flying east; evening light pushes it later, which helps after flying west. For very large eastward jumps (8 or more hours), early-morning light in the first couple of days can push the clock the wrong way, so the tool suggests seeking late-morning light instead. Shifting your bedtime an hour a day for a few days before you leave, switching to destination time on the plane, short naps, and limiting alcohol and late caffeine all help. Shifts of more than 12 hours are treated as the shorter way round. Honest limits: people vary widely, and these are general tips, not medical advice. Talk to a doctor before using melatonin or sleeping pills. The time zone converter and the sleep calculator are related.

Frequently asked questions