WorldClockTools.

Travel planner

Jet lag recovery planner.

Plan your pre-flight prep and recovery days based on time zones crossed.

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Recovery timeline

Sample eastbound plan — sleep/wake blocks

Local hours
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T−3
T−2
T−1
Flight
T+1
T+2
Sleep window Awake / adjustment

Recovery

How to use the recovery plan well

Jet lag is easier to handle when you start before the flight. The strongest use of this page is to decide when to begin shifting sleep, meals, and light exposure instead of waiting until you have already landed. That is where the planner becomes more than a novelty countdown.

Once you arrive, the fastest improvements usually come from anchoring yourself to the destination morning: wake at the local target time, get bright light, and move meals onto the local clock immediately. This is especially important for eastbound trips, where your body is being asked to fall asleep earlier than it naturally wants to.

Variance

Why some trips feel much worse than others

The number of time zones crossed matters, but so do flight timing, direction of travel, sleep debt, and how much daylight changes between origin and destination. A six-hour eastbound overnight can feel harder than a longer westbound daytime trip because it compresses both the clock and the sleep window.

That is why this page belongs next to city, compare, and market-hour pages on the site. Real travel timing decisions are not only about clocks. They also depend on when you need to function at the destination and how quickly your body can adapt to the new local day.

How to plan your jet lag recovery

A five-step walkthrough for using the planner to map pre-flight prep, in-flight strategy, and day-by-day recovery once you arrive.

  1. Enter your origin and destination time zones

    Pick the city or zone you are flying from and the city or zone you are flying to. The planner uses the difference between the two zones to estimate how many time zones you are crossing.

  2. Set your departure and arrival dates

    Choose the calendar date you are leaving and the date you arrive. The planner uses these to schedule pre-flight prep days and on-the-ground recovery days against your real itinerary.

  3. Start shifting your schedule two to three days before the flight

    For trips crossing four or more zones, move your bedtime, wake time, meals, and bright-light exposure 30 to 60 minutes per day toward the destination. Eastbound trips benefit from earlier light; westbound trips benefit from evening light.

  4. Anchor to the destination clock as soon as you land

    On arrival, wake at the local target time, get bright outdoor light immediately, and move meals onto the local schedule. This is the single fastest way to pull your circadian rhythm onto destination time.

  5. Follow the recovery timeline for the next several days

    Plan one full day of recovery per time zone you crossed eastbound, and roughly two-thirds of a day per zone westbound. Use the day-by-day timeline below the planner to know which mornings to push light exposure and which evenings to protect sleep.

Questions

Frequently asked questions

How long does jet lag last after flying east?
A useful rule of thumb is roughly one full day of recovery per time zone you crossed eastbound. So a five-hour eastbound flight (say London to New York's reverse, or NYC to Western Europe) typically takes 4 to 6 days to fully resolve, while an eight-hour shift can take a week or more. Eastbound is harder than westbound because your body is being asked to sleep earlier than its internal clock wants to.
What's the best way to recover from jet lag?
Anchor to the destination clock as fast as possible: wake at the local target time, get bright outdoor light within the first hour, and move meals onto the local schedule the same day you land. Avoid napping in the destination afternoon if you can — it pushes recovery back. For trips crossing four or more zones, start shifting your sleep window 30 to 60 minutes per day toward the destination two to three days before you fly.
Why is east-to-west travel easier than west-to-east?
The human circadian rhythm naturally runs slightly longer than 24 hours, so it's easier for your body to stretch a day (westbound) than to compress one (eastbound). Westward travel lengthens the day and asks you to stay up later, which most people find easy. Eastward travel shortens the day and asks you to fall asleep before your body is ready — which is why a six-hour eastbound trip can feel worse than a longer westbound one.
Does jet lag get worse as you get older?
Generally yes. The circadian system becomes less flexible with age, so the same time-zone shift takes longer to recover from at 60 than at 25. Older travelers benefit more from pre-flight schedule shifting and from being strict about destination-time light exposure on arrival. Hydration, avoiding alcohol on the flight, and protecting the first night's sleep matter more, not less, as you age.
Can I prevent jet lag entirely with melatonin or sleep aids?
Not entirely — no pill resets your circadian clock instantly. A small dose of melatonin (0.3–1 mg) at the destination bedtime for the first few nights can help speed adaptation, especially eastbound. Sleep aids only mask the wake-cycle problem; they don't shift the underlying clock. Bright light at the right time of day is a stronger lever than any supplement.
What is jet lag, medically speaking?
Jet lag is a temporary circadian rhythm sleep disorder caused by rapid travel across several time zones. The internal body clock, set by the suprachiasmatic nucleus in the brain, stays aligned to the origin time zone while the destination runs on a different schedule. That misalignment produces daytime sleepiness, night-time wakefulness, reduced concentration, and digestive upset until the clock resynchronizes.
How many time zones does it take to get jet lag?
Most people notice meaningful jet lag once they cross roughly three or more time zones. Shorter shifts of one or two zones usually feel like mild tiredness that resolves within a day. The severity grows with the number of zones crossed and is generally worse traveling eastward than westward for the same number of zones.
Does melatonin actually help with jet lag?
Used correctly, low-dose melatonin near the destination bedtime can speed circadian adaptation, with the strongest evidence for eastward travel across multiple zones. The timing of the dose matters more than its size — taken at the wrong hour it can shift the clock in the wrong direction. It is a circadian-timing aid rather than a sleeping pill, and checking with a clinician and local regulations is sensible.

People also ask

How long does jet lag last after flying east?

A useful rule of thumb is roughly one full day of recovery per time zone you crossed eastbound. So a five-hour eastbound flight (say London to New York's reverse, or NYC to Western Europe) typically takes 4 to 6 days to fully resolve, while an eight-hour shift can take a week or more. Eastbound is harder than westbound because your body is being asked to sleep earlier than its internal clock wants to.

What's the best way to recover from jet lag?

Anchor to the destination clock as fast as possible: wake at the local target time, get bright outdoor light within the first hour, and move meals onto the local schedule the same day you land. Avoid napping in the destination afternoon if you can — it pushes recovery back. For trips crossing four or more zones, start shifting your sleep window 30 to 60 minutes per day toward the destination two to three days before you fly.

Why is east-to-west travel easier than west-to-east?

The human circadian rhythm naturally runs slightly longer than 24 hours, so it's easier for your body to stretch a day (westbound) than to compress one (eastbound). Westward travel lengthens the day and asks you to stay up later, which most people find easy. Eastward travel shortens the day and asks you to fall asleep before your body is ready — which is why a six-hour eastbound trip can feel worse than a longer westbound one.

Does jet lag get worse as you get older?

Generally yes. The circadian system becomes less flexible with age, so the same time-zone shift takes longer to recover from at 60 than at 25. Older travelers benefit more from pre-flight schedule shifting and from being strict about destination-time light exposure on arrival. Hydration, avoiding alcohol on the flight, and protecting the first night's sleep matter more, not less, as you age.

The science of jet lag

Why crossing time zones disrupts the body clock

Jet lag is a circadian rhythm sleep disorder: a temporary mismatch between the internal body clock and the destination's day. These notes explain the biology behind the planner above so the recovery estimate makes sense.

The circadian clock runs slightly long

The body's master clock sits in the suprachiasmatic nucleus of the hypothalamus. Left with no time cues, the human circadian rhythm free-runs with an average period close to 24.2 hours — slightly longer than a calendar day. Because the natural tendency is to drift later, the clock stretches a day far more easily than it compresses one.

Light is the dominant zeitgeber

A zeitgeber (German for "time-giver") is any external cue that resets the clock. Light reaching the retina is by far the strongest: bright morning light advances the clock (shifts you earlier), while bright evening light delays it (shifts you later). Meals, exercise, and social schedules nudge the clock too, but none rivals light, which is why exposure timing is the central lever in any recovery plan.

Why eastward travel is harder

Flying east shortens your day and asks the clock to advance — to fall asleep and wake earlier than it wants to. Flying west lengthens your day and asks the clock to delay, which aligns with its natural drift toward later. The asymmetry is real and well documented: most travelers adapt roughly one hour per day going west but only about 1.5 days per hour going east for large shifts.

The one-day-per-timezone heuristic

A common rule of thumb is that full recovery takes about one day per time zone crossed. It is a useful planning starting point, but a loose one: direction of travel, individual chronotype, age, sleep debt, and how strictly you control light all change the real figure. Treat it as an upper-bound estimate for eastbound trips and an overestimate for many westbound ones.

Circadian misalignment, not just tiredness

Jet lag is not ordinary fatigue. It is a temporary mismatch between the internal clock and the destination's day — so digestion, alertness, body temperature, and hormone release are all still keyed to the origin time zone. That is why symptoms include daytime sleepiness, night-time wakefulness, poor concentration, and gut upset, and why a single long sleep does not fix it.

Limits of the recovery estimate

Any planner, including this one, gives an estimate, not a medical prediction. Trips crossing fewer than three zones rarely cause real jet lag. Beyond that, recovery speed varies widely between people, and partial adaptation — feeling mostly normal — usually arrives well before full circadian alignment. Use the timeline to plan, not as a guarantee.
The circadian system is run by the suprachiasmatic nucleus and entrained chiefly by light. Recovery is the process of re-entraining that clock to a new local day — which is why timing light, sleep, and meals matters more than simply resting.

Practical recovery

What actually shifts the clock faster

The strongest interventions are behavioral and time-sensitive. Each note below pairs with the day-by-day timeline above: decide when to start, then control light, sleep, and intake against the destination clock.

Pre-flight schedule shift

For trips crossing four or more zones, begin shifting your sleep and wake times two to three days before departure — earlier for eastbound travel, later for westbound — by 30 to 60 minutes per day. Move meals and light exposure with the schedule. Arriving partly adapted shortens the work still left to do on the ground.

Light exposure timing

Going east, seek bright light in the destination morning and avoid it in the early hours after a very large shift, when morning light can accidentally push the clock the wrong way. Going west, get light in the late afternoon and evening to delay the clock. Outdoor daylight is far brighter than indoor lighting and is the most effective and lowest-risk tool available.

Melatonin timing

Low-dose melatonin (commonly 0.5 to 5 mg) taken near the destination bedtime can help the clock shift, and the evidence is strongest for eastward travel across several zones. Timing matters more than dose; taken at the wrong hour it can shift the clock the wrong way. It is a supplement, not a sedative, and it is sensible to check local regulations and consult a clinician first.

Caffeine and alcohol strategy

Caffeine can boost daytime alertness at the destination but should be avoided within several hours of the local bedtime, since it lengthens the time to fall asleep. Alcohol fragments sleep and worsens dehydration; the CDC advises minimizing it around flights. Neither shifts the circadian clock — they only mask or worsen symptoms.
None of these tactics resets the clock instantly. They speed a natural process. For frequent or severe jet lag, or before using melatonin, the CDC advises consulting a clinician — this page is informational and not medical advice.