Certified tool

Jet Lag Planner

Estimate zone change and recovery days from platform time-zone data. Not medical advice.

Origin time zoneDestination time zoneDeparture local dateDeparture local timeArrival local dateArrival local time

Heuristic, not medical advice

5 recovery days

eastbound shift of 5 hours (UTC-05:00 → UTC+00:00).

Elapsed flight time 420 minutes, from platform time-zone offsets only.

Offsets come from the platform IANA time-zone database via Intl. No invented zone rules.
Eastbound recovery days = ceil(hours). Westbound = ceil(0.5 × hours). This is a heuristic.
A spring-forward wall time that does not exist is rejected.
This is not medical advice and not a generic time-zone converter.