Free · Time difference · Recovery
Jet Lag
& Time Difference Calculator
Know the time difference, your local arrival time and how many days to adjust.
Cities & UTC
Arrival time
Recovery days
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Your flight
Custom UTC offsets (optional)
Jet lag comes from crossing time zones. Reset to destination time immediately and get morning sunlight to adjust faster.
Your trip
Time difference
+9 h
destination is ahead of departure
Arrival (local)
08:00
Time zones crossed
9
Estimated jet lag recovery
~9 days
Eastbound flights are harder — one day per zone.
To adjust faster
✔ Set your watch to destination time on the plane
✔ Get bright sunlight in the morning
✔ Hydrate, limit caffeine after noon, nap under 30 min
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East is harder
Flying east advances your clock and is harder on the body. Flying west is generally gentler — plan accordingly.
Light is the reset button
Morning sunlight at your destination is the strongest signal to shift your body clock. Get outside early.
One day per zone
A useful rule: expect about a day of adjustment per time zone crossed eastbound, half that westbound.
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FAQ
Jet lag FAQ
What causes jet lag?
Your body's internal clock (circadian rhythm) is slower to adjust than your watch. Flying across time zones misaligns it with the new day-night cycle, causing fatigue, poor sleep and brain fog.
How long does jet lag last?
A common rule is about one day of adjustment per time zone crossed when flying east, and about half that flying west. A 6-zone trip means 3–6 days of adjustment.
Is it worse flying east or west?
Eastbound (e.g., US to Europe) is usually harder, because it advances your clock — your body must go to bed earlier. Westbound is generally easier.
How do I reduce jet lag?
Reset to destination time immediately, get sunlight in the morning, stay hydrated, avoid caffeine late in the day and take short naps. Some use melatonin under medical advice.
What is the time difference calculator for?
It tells you the exact hour offset between two cities and your local arrival time — so you can plan calls, meetings and sleep schedules.
Does flying north-south cause jet lag?
No — jet lag comes from crossing time zones east-west. North-south flights cause travel fatigue but not the same clock misalignment.
What should I do on the flight?
Set your watch to destination time, sleep or stay awake according to the new schedule, drink water, move around, and skip heavy meals.
Is melatonin safe for jet lag?
Short-term melatonin at bedtime is widely used and considered safe for most adults, but check with your doctor, especially with medications or health conditions.