Flying London (LHR) to New York (JFK) shifts your body clock 5 hours westward, which typically means about 4 days to adjust — moderate jet lag.
The calculator opens with LHR → JFK already filled in.
Build my LHR → JFK planEach recommendation below is graded by how strongly published research supports it, with the source it comes from. Optimal timing depends on your travel direction, the number of time zones crossed and your own circadian phase, so treat the schedule as a starting point.
Bright light in the local evening helps delay your body clock when travelling west.
CDC Yellow Book 2026Early light can advance your clock and work against a westward shift during the first days.
NIH — Circadian rhythmsMoving sleep and wake times 30-60 minutes later for a few nights gives your clock a head start on a westward trip.
CDC Yellow Book 2026Sleeping, eating and being active on local time gives your body consistent cues about the new day.
CDC Yellow Book 2026Low-dose melatonin near the local bedtime can help with sleep timing after crossing several zones; timing matters more than dose.
Cochrane review — Melatonin for jet lagCaffeine can help you stay awake during local daytime, but late doses tend to delay sleep onset.
CDC Yellow Book 2026Arriving without a large sleep debt makes the first days easier, even when few time zones are involved.
CDC Yellow Book 2026This is general travel information, not medical advice. Talk to a clinician before using melatonin or sleep medication, especially if you are pregnant, take other medication or have a sleep disorder.
Get flight times, time zone comparisons, and a personalized jet lag plan in seconds.
Start Planning