Jet lag calculator
Pick your origin and destination — we'll work out how many time zones you're crossing and how long you'll need to adjust.
How jet lag is estimated
We look up the IANA time zone for both airports, compute the difference in current UTC offset, and apply the standard 1 day per time zone rule — multiplied by 1.5 if you're flying east.
days_to_adjust = zones_crossed × (eastbound ? 1.5 : 1.0)This formula is widely cited in sleep-medicine literature as a working approximation. Real recovery depends on age, sleep quality, light exposure, and how much your sleep was disrupted on the flight itself.
Recovery tips that work
- Daylight on arrival: 30+ minutes outside is the strongest reset signal for your circadian clock.
- Eat on local time: meal timing shifts your gut clock as much as light shifts your brain clock.
- Skip alcohol on the plane: it fragments REM sleep more at altitude than on the ground.
- Pre-shift if it's 3+ zones: move your sleep by 30–60 min toward the destination for 2–3 days before you fly.
Frequently asked questions
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We use the standard rule: roughly 1 day to recover for each time zone crossed, but eastbound travel is harder (about 1.5× westbound), because your body clock would rather drift later than earlier. So a 6-hour eastbound flight = ~9 days; the same flight westbound = ~6 days.
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Most people's circadian rhythm naturally runs slightly longer than 24 hours, so 'staying up later' (westbound) is easier than 'going to sleep earlier' (eastbound). Travelling east compresses the day; travelling west stretches it.
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Yes. Arrival in the morning makes adjustment easier — you can soak up daylight. Late-night arrivals are tougher because you'll want to sleep but your body may resist. We don't factor that into the days-to-adjust number, but plan around it where you can.
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Get sunlight on arrival, eat meals on the local schedule, avoid alcohol on the plane, and stay hydrated. For trips of 3+ time zones, start shifting your sleep by 30–60 min/day for 2–3 days before you fly.