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Jet Lag Calculator
Land ready — plan your sleep around the time zones
Why Jet Lag Hits So Hard
Jet lag isn’t tiredness from traveling — it’s your circadian clock disagreeing with the local time. Your body still thinks it’s 3 AM at home while the destination sun says noon. Until the clock resets (about one day per time zone eastward, slightly faster westward), sleep, digestion, and focus all misfire.
East vs. West: Why Direction Matters
Flying east is harder because it shortens your day — you must fall asleep earlier than your body wants, which fights melatonin timing. Flying west lengthens the day, which the body tolerates better. Plan accordingly: eastward trips deserve 3 days of pre-shifting; westward, 1–2 is enough.
The Light Trick (It Really Works)
Light is the strongest clock-resetter you have:
- Eastward: seek bright morning light at your destination, avoid bright light in the evening.
- Westward: seek bright evening light, avoid morning light.
- Get outside — daylight beats any lamp by 10x.
Frequently Asked Questions
How long does jet lag last?
Roughly one day per time zone crossed eastward, and about a day per 1.5 zones westward. A 6-zone eastward trip takes ~6 days to fully shake.
Should I nap when I arrive?
Only a 20-minute nap if you land well before evening — then stay up until local bedtime. Arriving at night? Go straight to sleep.
Does melatonin help jet lag?
Yes — 0.5–3 mg at local bedtime for the first few nights helps eastward travelers especially. It’s the best-studied jet lag remedy.
Why is eastward jet lag worse?
It compresses your day, forcing sleep earlier against your melatonin rhythm. Westward stretches the day, which the body clock accepts more easily.
Can I prevent jet lag before flying?
Partially: shift your bedtime 1 hour per day toward destination time for 3 days pre-flight, and time your light exposure. The calculator above builds the plan.
Disclaimer: General wellness information only, not medical advice.