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Calculate jet lag recovery time and get direction-specific tips for any international flight.
Jet lag is a temporary sleep disorder caused by rapid travel across multiple time zones, disrupting the body's internal circadian clock. Eastward travel is generally harder to adjust to than westward travel.
← Westward Travel Tips
| Route | TZ Diff | Severity |
|---|---|---|
| New York → London | 5h | Moderate |
| Los Angeles → Tokyo | 17h (or -7h) | Severe |
| London → Singapore | 8h | Severe |
| New York → Los Angeles | 3h | Mild |
| Sydney → Dubai | 6h | Moderate |
| New York → Sydney | 15h (or -9h) | Severe |
Most people adapt within 1 day
Expect 2–5 days of adjustment
Plan for 5–7 days to fully adjust
May take 1–2 weeks to fully recover
Formula
Adjustment Days = TZ Difference × 1.0 (eastward) or × 0.75 (westward)TZ Difference = absolute difference in UTC offsets between departure and arrival time zones
1.0 (eastward) = eastward travel is harder — approximately 1 day per time zone crossed
0.75 (westward) = westward travel is easier — approximately 0.75 days per zone
Worked Example
New York (UTC-5) → Tokyo (UTC+9), eastward
Did you know? The human circadian rhythm naturally runs slightly longer than 24 hours — which is why westward travel (extending your day) is biologically easier than eastward travel (compressing it). This asymmetry is well-documented in sleep medicine research.
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