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Jet lag planner: bed and wake times for your trip
For travellers crossing time zones who want each night's bedtime in local clock time, not just a count of recovery days. Enter both time zones and your usual sleep to get a night-by-night plan for the days before and after you fly, with light times.
UTC-5 to UTC+1
Why this plan?
Jet lag planner
More settings: shifting before you fly, direction
Use each place's UTC offset on the travel date; daylight saving time changes it.
Working nights instead? Use the night-shift sleep planner.
Jet lag east vs west: how many days to adjust, by time zones crossed →
There’s no perfect night, only a better-planned one.
Sleeping somewhere new on this trip? The Lull app's six sounds are built in, play offline and stop before your phone's alarm.
See the Lull appFlying from UTC-5 to UTC+1 and moving your sleep for 2 days before you go? You are back at your usual bedtime after 4 nights at the destination.
Where a travel plan can go wrong
The rates are averages from the CDC Yellow Book, and real people adjust faster or slower. The planner cannot know your own body clock, how much you slept on the flight or how long you are staying, and its light windows and the rule for picking a direction are our own simplifications. For a stay of a day or two, the Yellow Book mentions keeping to home sleep hours instead. The planner does not cover night shifts, medicines or melatonin.
See a doctor before a trip if you take medicines on a fixed schedule, have a sleep or mood condition, or if jet lag regularly leaves you unable to function. This page is general information, not medical advice: read our disclaimer.
How the planner works
It starts from the difference between the two UTC offsets and works out how many hours your body clock would have to move earlier (advance) or later (delay) to match the destination. By default it picks the direction that needs fewer hours; a tie goes to later, and you can choose either yourself. The Yellow Book gives average rates of 1 hour a day when the clock has to move earlier, usually flying east, and 1.5 hours a day when it moves later, usually flying west.
Before you fly, it can shift your sleep 1 hour a day toward the destination for up to 3 days, which the Yellow Book says may shorten the time needed to adjust. Each night at the destination is then your usual sleep window, moved by the hours still left to shift. Bedtimes outside 8:00 PM to 3:00 AM are flagged as hard to keep.
Worked example: flying east
You live at UTC-5, fly to UTC+1, usually sleep 11:00 PM to 7:00 AM and shift for 2 days before you go. The destination is 6 hours ahead; moving earlier by 6 hours is fewer than moving later by 18, so this is an advance. The days before the flight take off 2 hours, with bedtimes of 10:00 PM and then 9:00 PM. The 4 hours left take 4 nights at 1 hour a day: bed at 2:00 AM, 1:00 AM, 12:00 AM, 11:00 PM, the last being your usual time. Without shifting first, the same trip takes 6 nights.
Going the other way, UTC-5 to UTC-8 needs a 3 hour delay at 1.5 hours a day: 2 nights, with bed at 9:30 PM and then 11:00 PM.
Why east is usually harder
The Yellow Book explains that for most people it is easier to delay the body clock than to advance it, because the clock's natural day runs slightly longer than 24 hours. Flying east asks the clock to move earlier, so it adapts at about 1 hour a day against 1.5 hours a day going west. A long trip can be planned either way round: from UTC-5 to UTC+9 is 14 hours earlier or 10 hours later, and the planner picks the later, smaller shift unless you choose otherwise. The Yellow Book gives no rule for choosing, so that default is ours.
Light, and the body clock's low point
The Yellow Book says bright light in the morning, after the clock's low point about 2 to 4 hours before your usual wake time, moves the clock earlier, while light in the evening generally moves it later. The planner turns that into windows, which are our own rule of thumb: when moving earlier, bright light for 3 hours after waking and low light for 2 hours before bed; when moving later, bright light from 4 hours to 1 hour before bed and low light for 2 hours after waking. In the first example, night one at the destination is sleep from 2:00 AM to 10:00 AM, so its windows are bright light 10:00 AM to 1:00 PM and low light from 12:00 AM. The low-light window before bed is the top of the 1 to 2 hours NIOSH gives for keeping light low before bedtime. The Yellow Book adds that the best timing depends on the direction and the number of time zones, so from a shift of 6 hours the planner marks its light times as approximate.
Landing day, short trips and naps
The plan shows how the first night sits against your landing time: if you land in the evening after its bedtime, it says to sleep when you arrive. The Yellow Book also notes that staying awake during the local day builds the drive to sleep at night, that short naps of 20 to 30 minutes can help you stay alert while longer naps may get in the way of night sleep, and that on short trips keeping home sleep hours is an option. On melatonin, the Yellow Book notes that it “is secreted by the pineal gland in the brain during darkness and it is suppressed during the day with light exposure”; this planner gives no timing for it.
The values behind this plan
Each row is one value this tool uses, with its tier: Primary = read off the source page, Secondary = reported by the source from another body, Studio rule = our own choice, with the reason given on the methodology page. The links in the result above go to the same rows there.
Quotes, notes and the date we last read each source are on the methodology and sources page.
Questions about jet lag
Is jet lag worse flying east or west?
For most people, east. The CDC Yellow Book says it is easier to delay the body clock than to advance it, with average rates of 1.5 hours a day westward and 1 hour a day eastward.
How many days does it take to adjust?
The planner divides the hours your clock has to move by the daily rate, after any shifting before you fly. The UTC-5 to UTC+1 trip above takes 6 nights with no shifting first and 4 with 2 days of it.
Does shifting sleep before the trip help?
The Yellow Book says shifting sleep 1 hour a day, later for westward and earlier for eastward travel, in the 2 to 3 days before a trip may reduce the time needed to adjust.
When should I get light after flying east?
The Yellow Book says morning light after the body clock's low point, about 2 to 4 hours before your usual wake time, moves the clock earlier. The planner's light windows build on that and are our own rule of thumb.
Can it plan night shifts?
No. Working nights in your own time zone is a different problem, covered by the night-shift sleep planner.
Is my trip stored anywhere?
No. The plan is worked out in your browser. The share link holds only the time zones, times and choices in the form, and only if you copy it.
More questions about the site, its sources and privacy are answered in the Lull FAQ.