Jet lag Europe to US usually lasts about 4 days from London to New York (5 hours) and about 6 days from Paris to Los Angeles (9 hours), because flying west lets your body clock shift later, roughly 1.5 hours a day. The classic symptoms are crashing by dinnertime and waking at 3 or 4 AM for the first few nights.
This is the return leg. For the flight over, see our US to Europe plan. For your own route and sleep times, use the jet lag calculator.
Free toolJet Lag CalculatorDays to adjust, plus a shift-before-you-fly schedule.Is jet lag worse going to Europe or coming back?
For your body clock, coming back is easier, but plenty of people feel worse after the return trip. Flying west asks your clock to run later, which it does fairly willingly. East vs. west explains why.
The return still catches people out, for reasons that have little to do with the body clock:
- You arrive already short on sleep. Late dinners, early tours and a 3 AM wake-up in your first nights abroad add up.
- The travel day is long. From a 7:00 AM wake-up in Paris to a 10:30 PM bedtime in Los Angeles is 24.5 hours awake. London to New York is 20.5.
- You go straight back to work. There's no easy first day to absorb it.
- Early waking feels like insomnia. Waking at 4 AM and not getting back to sleep is normal westward jet lag, not a sleep problem.
How long does jet lag Europe to US last?
About 3 to 6 days, depending on how many time zones you cross and how long you were away. These use the calculator's rule of about 1.5 hours a day for westward shifts, rounded up.
| Route home | Time difference | Days to adjust |
|---|---|---|
| London to New York | 5 hours | about 4 |
| Paris or Rome to New York | 6 hours | about 4 |
| London to Chicago | 6 hours | about 4 |
| London to Los Angeles | 8 hours | about 6 |
| Paris to Los Angeles | 9 hours | about 6 |
Europe and the US change their clocks on different weekends, so for a few weeks in March and in late October the gap is one hour smaller.
Short trip, smaller jet lag
If you weren't in Europe long enough to adjust, there's less to undo on the way home. Assuming you adjusted about an hour a day while away:
| Nights in Europe | London to New York | Paris to Los Angeles |
|---|---|---|
| 3 | about 2 days | about 2 days |
| 5 | about 4 days | about 4 days |
| 7 | about 4 days | about 5 days |
| 10 or more | about 4 days | about 6 days |
Before you leave Europe: go to bed later
In your last 2 or 3 nights abroad, go to bed and get up an hour later each night, and get evening light. It's the easiest jet lag prep there is, because late dinners already push you that way.
From London, with a usual 11:00 PM to 7:00 AM routine, that's bed at midnight, then 1:00 AM, then 2:00 AM, waking at 8:00, 9:00 and 10:00 AM. Three nights of that cuts London to New York from about 4 days of adjustment to about 2, and Paris to Los Angeles from about 6 days to about 4.
On the flight home
Most flights from Europe to the US leave late morning or early afternoon and land the same afternoon, so stay awake for most of it. A typical example: London at 11:00 AM, New York at 2:00 PM, when your body thinks it's 7:00 PM. Or Paris at 1:30 PM, Los Angeles at 4:00 PM, when your body thinks it's 1:00 AM.
- Stay in the light for most of the flight: shade up if your row agrees, reading light on. Light in your body's evening helps it shift later.
- If you must sleep, keep it to one nap, no more than one 90-minute cycle, in the first half of the flight.
- Stay up until at least 9:00 PM local time after you land.
Night by night: why you wake at 4 AM
After flying west, 4 AM at home feels like mid-morning to your body, so you wake up and can't get back to sleep. The tables show what 10:30 PM and 4:00 AM feel like each night, assuming you were fully adjusted to Europe.
The light plan is built around your body clock's low point, its sleepiest time, about 3 hours before your usual wake-up. Light in the hours before the low point pushes your clock later. Light in the few hours after it pulls your clock earlier, the wrong direction.
London to New York (5 hours)
| Night | 10:30 PM feels like | 4:00 AM feels like | Light plan |
|---|---|---|---|
| Night 1 | 3:30 AM | 9:00 AM | Daylight all afternoon and evening |
| Night 2 | 2:00 AM | 7:30 AM | Same. Mornings are fine |
| Night 3 | 12:30 AM | 6:00 AM | Keep it dim until about 6:00 AM |
| Night 4 | 11:00 PM | 4:30 AM | Keep it dim until about 7:30 AM |
| Night 5 | adjusted | Morning light now helps |
Paris to Los Angeles (9 hours)
| Night | 10:30 PM feels like | 4:00 AM feels like | Light plan |
|---|---|---|---|
| Night 1 | 7:30 AM | 1:00 PM | Daylight until 7:00 PM, then low lights |
| Night 2 | 6:00 AM | 11:30 AM | Daylight until 8:30 PM, then low lights |
| Night 3 | 4:30 AM | 10:00 AM | Daylight into the evening |
| Night 4 | 3:00 AM | 8:30 AM | Daylight all afternoon and evening |
| Night 5 | 1:30 AM | 7:00 AM | Keep it dim until about 5:00 AM |
| Night 6 | 12:00 AM | 5:30 AM | Keep it dim until about 6:30 AM |
| Night 7 | adjusted | Morning light now helps |
Everyone shifts at a slightly different speed, so treat these as a guide.
Your first few days home
- When you wake at 4 AM, keep the lights off and rest. If you're up for good, stay in dim light rather than switching on bright overheads.
- Don't nap past mid-afternoon. A 20-minute nap is fine. A long late nap feeds the early-evening crash and the early waking.
- Watch late caffeine. You'll want coffee at 3 PM, but for a 10:30 PM bedtime an 8 oz coffee should be done by about 12:50 PM. The caffeine calculator finds your cutoff.
- Keep your normal wake-up time once mornings stop being a problem.
If the trip also left your schedule drifting late, resetting your sleep after vacation covers the rest.