London to Los Angeles delays your body clock by about eight hours – a westward trip, the easier direction, but a large shift. Most travellers feel moderately-to-strongly jet-lagged for around five days. Expect early waking at first, and use bright evening light in Los Angeles to keep your clock moving later.
London to Los Angeles at a glance
| Time difference | Los Angeles is 8 hours behind London for most of the year |
|---|---|
| Direction | Westward – your clock delays (easier direction, big shift) |
| Time zones crossed | About 8 |
| Jet lag estimate | Roughly 6 out of 10 (moderate to high) |
| Body clock on arrival | You land in the afternoon; your body reads late evening or night |
| Adaptation | Around 5 days |
| Flight time | About 11 hours |
These figures are transparent estimates, not clinically validated. The exact time difference depends on the date; the calculator resolves it for your trip.
Time difference and direction
Los Angeles is eight hours behind London through most of the year. You travel west, so your clock delays – the easier direction – but eight hours is a big move, so this is a meaningful long-haul rather than a gentle hop. The east-west calculator shows the effective delay, and the jet lag duration calculator gives a recovery range.
Jet lag estimate and body clock
Expect a moderate-to-high jet lag, around six out of ten. Flights usually leave London around midday and reach Los Angeles in the afternoon, but by then your body reads late evening or night, so you will tire early. For the first few days you will likely wake before dawn, the classic westward-trip pattern, until your clock catches up.
Adaptation: how long it lasts
Plan for about five days. An eight-hour westward shift resolves faster than the same shift eastward, but it still takes several days because the clock delays only around ninety minutes a day. Consistent evening light and a firm local schedule pull you toward the fast end. See how long does jet lag last.
Before the flight
In the two or three nights before departure, shift your bedtime later by an hour or so each night to start the delay at home. Arrive rested – an eight-hour shift is hard enough without a sleep debt on top.
During the flight
This is a long daytime westbound flight, so stay awake for most of it and sleep only late, if at all. Set your watch to Los Angeles time on boarding, keep moving and hydrating, avoid alcohol, and keep caffeine to the first half of the flight.
After arrival
Stay up to a normal Los Angeles bedtime, helped by bright late-afternoon and evening light, which delays your clock the right way. On the first mornings, protect yourself from very early light with sunglasses so you do not drift back toward London time. Keep meals on local time. The light exposure planner gives the exact windows.
Calculate your personal plan
Get a day-by-day schedule tailored to your exact departure time and sleep habits, with this route already filled in.
Sources
- U.S. Centers for Disease Control and Prevention – CDC Yellow Book, “Jet Lag” chapter – direction asymmetry, timed light, pre-travel adjustment.
- NHS – “Jet lag” (nhs.uk/conditions/jet-lag/), last reviewed 31 May 2023.
- Sleep Foundation – “Jet Lag” educational overview.
- IANA Time Zone Database – offsets for Europe/London and America/Los_Angeles.