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Jet lag calculator and sleep plan

See how long jet lag will last for your flight, then get a day-by-day plan: when to shift your sleep before you go, when to sleep on the plane, and when to seek or avoid light after you land.

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JFK · John F Kennedy International Airport

LHR · London Heathrow Airport

Flight duration
hours
minutes
Your usual sleep at home

Optional. The plan keeps the same sleep length and moves it to the new clock.

About 5 days to adjust to London time

London is 5 hours ahead (eastward). Estimated recovery: about 5 days without preparation. About 2 days with a 3-day head start.

Time zones crossed
5 eastwardEastward trips are usually harder.
With this plan
About 2 days after landingAfter shifting 3 hours before you fly.
You land (London time)
Fri 7:25 AM GMT
Your body clock (New York time)
Fri 2:25 AM EST

General guidance, not medical advice. Recovery times are estimates and vary from person to person.

Your day-by-day jet lag plan

A sleep and light schedule for New York to London, one day at a time. Times are local to where you are that day.

  • Sleep
  • Get bright light
  • Avoid bright light

Before you fly

Times in New York time

  1. 13 days before

    Monday, November 9

    1 hour earlier

    Go to bed and get up 1 hour earlier than usual.

    1. 7:00 AMto 9:00 AMGet bright lightGo outside or sit by a bright window
    2. 8:00 PMto 10:00 PMAvoid bright lightDim screens; sunglasses if you’re outside
    3. 10:00 PMto 6:00 AMSleepLights out, phone away

  2. 22 days before

    Tuesday, November 10

    2 hours earlier

    Go to bed and get up 2 hours earlier than usual.

    1. 6:00 AMto 8:00 AMGet bright lightGo outside or sit by a bright window
    2. 7:00 PMto 9:00 PMAvoid bright lightDim screens; sunglasses if you’re outside
    3. 9:00 PMto 5:00 AMSleepLights out, phone away

  3. 3Day before you fly

    Wednesday, November 11

    3 hours earlier

    Go to bed and get up 3 hours earlier than usual.

    1. 5:00 AMto 7:00 AMGet bright lightGo outside or sit by a bright window
    2. 6:00 PMto 8:00 PMAvoid bright lightDim screens; sunglasses if you’re outside
    3. 8:00 PMto 4:00 AMSleepLights out, phone away

In the air

Sleep times in London time

  1. Flight JFK → LHR

    Thursday, November 12

    Switch to London time

    Takes off

    Thu 7:30 PM EST

    Fri 12:30 AM GMT in London

    Lands

    Fri 7:25 AM GMT

    Fri 2:25 AM EST on your body clock

    1. 1:15 AMto 6:40 AMSleep on the planeLights out, phone away
    • Set your watch and phone to London time when you board.
    • It is night in London from 1:15 AM to 6:40 AM on this flight: try to sleep then. An eye mask and earplugs help.
    • Drink water through the flight, and go easy on alcohol and caffeine.

After you land

Times in London time

  1. 5Day 1 in London

    Friday, November 13

    Body clock 2 hours behind

    Body clock about 2 hours behind London. Stay up until about 11:00 PM local time. If you must nap, keep it short and early in the afternoon.

    1. 8:10 AMto 3:00 PMGet bright lightGo outside or sit by a bright window
    2. 11:00 PMto 7:00 AMSleepLights out, phone away

  2. 6Day 2 in London

    Saturday, November 14

    Body clock 1 hour behind

    Body clock about 1 hour behind London. Keep to local meal and sleep times.

    1. 7:00 AMto 2:00 PMGet bright lightGo outside or sit by a bright window
    2. 11:00 PMto 7:00 AMSleepLights out, phone away

  3. 7Day 3 in London

    Sunday, November 15

    On London time

    Your body clock should be close to London time now. Keep a regular routine and morning daylight.

    1. 7:00 AMto 9:00 AMGet bright lightGo outside or sit by a bright window
    2. 11:00 PMto 7:00 AMSleepLights out, phone away

How the jet lag plan is worked out

No black box. Here is every step, using the example above: New York (JFK) to London (LHR) on an overnight flight, sleeping 11 PM to 7 AM at home.

These are widely used rules of thumb, not a medical model. People adjust at different speeds. If you have a sleep condition, are pregnant or take regular medication, ask a doctor before changing your sleep.

  1. 1Time differenceEach airport's UTC offset is read for your travel dates, so daylight saving is included. London is 5 hours ahead of New York on November 13. A gap of more than 12 hours is planned the shorter way round the clock.
  2. 2Recovery estimateRule of thumb: the body clock moves about 1 hour a day after flying east and about 1.5 hours a day after flying west. 5 hours ÷ 1 hour a day = about 5 days to adjust with no preparation.
  3. 3Head startBedtime and wake time move 1 hour a day toward the destination for up to 3 days before the flight. That covers 3 hours, leaving 2 hours: about 2 days after landing.
  4. 4Sleep on the planeThe flight leaves at Thu 7:30 PM EST and lands at Fri 7:25 AM GMT. The plan suggests sleep where the flight overlaps your usual night in London time, leaving 45 minutes after take-off and before landing: 1:15 AM to 6:40 AM.
  5. 5Light windowsThe body clock's low point is taken as 2 hours before your usual wake time, on the body clock. After an eastward flight, light in the 8 hours after that point tends to move the clock earlier, so the plan says seek it, and avoid light in the 3 hours before. Westward, it is the reverse. Windows are trimmed to the hours you are awake.

How long does jet lag last?

Short answers on recovery time, sleep schedules and beating jet lag.

How long does jet lag last?

A widely used rule of thumb is about one day for each time zone you cross. The body clock tends to shift about 1 hour a day after flying east and about 1.5 hours a day after flying west, so a 6-hour eastward trip takes roughly 6 days and a 6-hour westward trip roughly 4. People vary, and shifting your sleep before you fly can shorten it.

How long does jet lag last from the USA to the UK?

New York to London is usually 5 hours ahead (4 hours for a few weeks in spring and autumn, when the clocks change on different dates). By the one-hour-a-day rule that is about 4 to 5 days to fully adjust without preparation. From the West Coast it is 8 hours, so about 8 days. Moving your bedtime earlier for a few days before the flight can cut that down.

How long does it take to recover from jet lag after flying west?

Usually less time than flying east. Using the common estimate of about 1.5 hours of adjustment a day, London to New York (5 hours west) takes roughly 3 to 4 days. Getting daylight in the late afternoon and evening, and staying up until local bedtime, helps.

How do you beat jet lag?

Start shifting your sleep toward the destination a few days before you go, switch your watch to destination time when you board, sleep on the plane only if it is night at your destination, then get daylight at the right times and go to bed at local bedtime from the first night. Keep naps short and drink water. The calculator turns these steps into times for your trip.

What jet lag sleep schedule should I follow?

Before an eastward trip, go to bed and get up about an hour earlier each day; before a westward trip, an hour later. After landing, sleep at your usual bedtime in local time, even if you do not feel tired, and get up at your usual local wake time. The day-by-day plan above shows the exact times.

Why is jet lag worse flying east?

Flying east means your day starts earlier, so your body clock has to move earlier. Most people find it easier to stay up later than to fall asleep earlier, which is why westward trips usually feel easier to adjust to.

Should I take melatonin for jet lag?

Some travelers use melatonin, but whether it suits you, and when and how much to take, is a question for a doctor or pharmacist. This calculator gives general guidance about sleep and light timing only. It is not medical advice.

Does TripCache make jet lag plans?

No. This calculator is a free tool on our site. The TripCache app organizes the trip itself: flights, hotels and bookings in one itinerary with local departure and arrival times, so you always know what time it is where you are going next. Live flight-status alerts are part of TripCache Pro.

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