How the jet lag calculator works
Your body clock runs on light. Light at the right time shifts it; light at the wrong time pushes it the wrong way. The calculator estimates when your body temperature is lowest (about 2.5 hours before your usual wake time), then times light, sleep, naps, meals and melatonin around that point as it moves each day.
East vs. west
Flying east, your clock must move earlier (advance), about 1 hour per day. Flying west, it moves later (delay), about 1.5 hours per day. For 10+ hours east, delaying the long way around is usually faster, and the plan switches automatically.
Kids by age
Children shift in smaller steps before the trip (15–30 minutes a day) and keep earlier bedtimes. Babies and toddlers keep their naps on local time. Teens, natural night owls, get extra emphasis on morning light when flying east.
Daylight saving time
Time differences are calculated for your actual travel dates, so DST changes on either end are handled.
Jet lag with kids: FAQ
How do you beat jet lag with kids?
Shift bedtimes 15–30 minutes a day for 2–3 days before you fly, switch everyone to destination time on the plane, get outdoor daylight at the right times after landing, keep naps short and early, and hold a consistent local bedtime and wake time. Most families adjust in 3–6 days after big trips.
How many days does jet lag last?
Roughly one day per time zone flying east and about two-thirds of a day per time zone flying west. Pre-shifting before the trip and well-timed light can cut that significantly.
Is jet lag worse flying east or west?
East is usually harder, because the body clock has to move earlier (advance), which it does more slowly than moving later. For 10 or more hours east, delaying the clock the long way around is often easier.
Can kids take melatonin for jet lag?
Only with your pediatrician's OK. When approved for children 4 and up, low doses of 0.5–1 mg about 30 minutes before bedtime for a few nights are typical. Melatonin is not recommended for babies and toddlers.
How much melatonin should adults take for jet lag?
0.5 to 3 mg about 30 minutes before local bedtime for 2–4 nights after flying east. Low doses shift the clock as well as high doses with less grogginess. Ask your doctor if you are pregnant, take medication or have health conditions.
Should my kids sleep on the plane?
Yes, if the flight overlaps nighttime at your destination. Do a mini bedtime routine at the start of that window. If it is daytime at your destination, keep kids awake and active, with only short naps.
Should toddlers nap after a long flight?
Yes, keep their usual naps but move them to local clock time and cap them so no nap ends after about 4 PM. Overtired toddlers sleep worse at night.
Should we adjust to local time on a short trip?
For trips of 3 days or fewer, stay close to home time and shift only partway. You avoid a second round of jet lag when you return.