Jet Lag Recovery Calculator
Estimate how many days it will take to recover from jet lag based on time zone difference and direction of travel.
What is Jet Lag Recovery Calculator?
The jet lag calculator estimates recovery time using research-backed rules: ~1 day per hour of time zone difference traveling east; ~2/3 of that traveling west.
Formula
Days = hours of time-zone difference × direction factor × age factor. East = 1.0; west = 0.67. Older travelers recover slower.
Worked example
NYC → London (5 hours east, age 35): 5 × 1.0 × 1.0 = 5 days. London → NYC (5 hours west): 5 × 0.67 × 1.0 ≈ 3.4 days.
How to use this calculator
- Enter the time-zone difference of your trip.
- Pick the direction.
- Enter age (older = slower recovery).
Frequently asked questions
Why is east harder than west?
You can't easily fall asleep earlier than your body wants (eastbound) but you can stay up later (westbound). The body adapts more easily to a longer day than a shorter one.
How do I minimize jet lag?
Adjust to the destination time zone before flying (start shifting bedtime 3 days early). Use bright daylight at the destination. Avoid alcohol on the flight. Consider melatonin if your doctor approves.
Does direction always matter?
For trips of 4+ time zones yes. For 1–3 zone shifts, jet lag is usually minor either direction.
Trans-Pacific is harder?
Yes — both because of the longer flight and because crossing 8+ time zones is enough to disrupt the body's circadian rhythm meaningfully.