How long does jet lag last?
About a day per time zone going west, and rather worse going east — with a long tail that catches people out on the return leg.
The short answer
Roughly one day per time zone travelling west, and about one and a half travelling east.
Six zones westward is three or four days. The same six eastward is commonly four to six. Individual variation is large.
The rough table
| Zones | Westward | Eastward |
|---|---|---|
| 2–3 | 1–2 days | 2–3 days |
| 4–6 | 3–4 days | 4–6 days |
| 7–9 | 4–6 days | 6–9 days |
| 10+ | 5–7 days | 8–12 days |
Beyond about ten zones the direction matters less, because the body sometimes adjusts by going "the long way round" — shifting in whichever direction is shorter for the internal clock rather than the one that matches your itinerary.
Why east is slower
The human circadian cycle runs slightly longer than 24 hours. Stretching a day — what westward travel asks — works with that drift. Compressing one works against it.
That is the whole asymmetry, and it is consistent enough to plan around: budget noticeably more recovery time for eastward trips.
Why it is not one clean recovery
Different systems re-sync at different rates. Sleep timing usually adjusts first; core body temperature, digestion and hormone rhythms lag behind, sometimes by days.
This is why you can be sleeping through the night in a new city and still feel slightly wrong for another few days — hungry at odd hours, flat in the afternoon, sharp at midnight. That is the slower systems catching up.
Coming home is often worse
Two reasons people underestimate the return leg.
Direction. A westward outbound trip means an eastward return, which is the harder one. London to Los Angeles is the easy direction; the flight home is not.
Behaviour. On arrival somewhere new you are outdoors, walking, exposed to daylight and motivated to adopt local hours. Coming home you go straight back to an indoor routine, which removes the strongest adjustment signal exactly when you need it.
There is a scenario about that.
What makes it shorter
Correctly-timed light exposure, immediate adoption of local hours, and avoiding long naps. Detail in how to avoid jet lag.
What makes it longer: sleeping in, staying indoors, and treating the first two days as recovery time in a dark hotel room.
Short trips
For a trip of two or three days across many zones, fully adjusting and then re-adjusting on return costs more than it saves.
For those, many frequent travellers deliberately stay on home time — schedule meetings in their own body's daytime where possible, keep eating and sleeping on the original clock, and accept being out of step with the location. It is not comfortable, but it avoids paying the adjustment twice in a week.
Related: Jet lag explained · Coming back is worse than going out
Timezone: World Clock Widget
A world clock, converter and live day/night map for iPhone — 325 cities, offline, no account.
Figures on this page are computed from the IANA time zone database. Last generated 2026-08-18.