Estimate your jet lag recovery timeline
Enter your route and sleep pattern to estimate how many days your body may need to re-sync.
Examples: New York = -5, London = 0, Paris = +1, Delhi = +5.5, Tokyo = +9
What this jet lag recovery calculator does
Jet lag is a mismatch between your internal body clock and the local time at your destination. This calculator estimates your adjustment window based on three practical factors: how many time zones you cross, whether you travel east or west, and your baseline sleep pattern.
It also gives you a simple pre-departure sleep-shift plan so you can start adapting before takeoff. This is especially useful for long-haul flights where your schedule shifts by 5+ hours.
Why eastbound trips usually feel harder
1) East travel requires a phase advance
Flying east means your local day becomes shorter. You need to fall asleep earlier than your body wants, which is generally tougher than staying up later.
2) West travel usually allows a phase delay
Flying west creates a longer day. Most people find it easier to delay bedtime than to advance it, so westbound adaptation is often faster.
How to use your result in real life
- Use light strategically: light is the strongest cue for shifting your clock.
- Anchor wake time: wake at the same local time every day, even after a rough night.
- Keep caffeine tactical: use in local morning/early afternoon only.
- Protect sleep opportunity: maintain a realistic wind-down routine and dark sleep environment.
Practical protocol for faster recovery
Before departure
Start shifting bedtime and wake time by 30-90 minutes per day toward destination time. Even 2-3 days of pre-adjustment can reduce first-night insomnia and daytime fatigue.
On flight day
Hydrate consistently, keep alcohol low, and switch your watch to destination time early. This mental cue improves adherence to your destination schedule on arrival.
After landing
Get daylight exposure at the right time, avoid long naps, and move your meals into destination time. If a nap is necessary, cap it at 20-30 minutes.
Limitations and safety note
This calculator provides an educational estimate, not a medical diagnosis. Recovery varies with age, stress, sleep debt, workload, and individual circadian sensitivity. If you have chronic insomnia, bipolar disorder, shift-work disorder, or are considering melatonin or prescription sleep meds, talk to a qualified clinician.
FAQ
How many days does jet lag usually last?
A common rule is roughly one day per time zone eastbound and slightly less westbound, but behavior and light exposure can speed or slow adaptation.
Can I fully adapt on a short trip?
Sometimes no. For brief trips (2-4 days), many travelers perform better by partially adapting while protecting sleep and alertness.
Does melatonin help?
For some people, low-dose melatonin timed correctly can help, especially on eastbound trips. Timing matters more than dose.