Vietnam Jet Lag Calculator

Two Vietnam specifics compound the shift: Hanoi sits at 19 m (altitude makes poor sleep feel worse), and Southeast Asia sits on the Asia travel circuit most Vietnam itineraries follow. London departures face 7 hours, New York 12, Tokyo 2 and Sydney 3 — each figure feeds the recovery estimate for Hanoi at UTC+7.

One useful constant: Hanoi — and with it the Vietnam clock — stays pinned to UTC+7 for the whole trip. Reference frame for Vietnam: Hanoi keeps UTC+7 and sits 19 m above sea level in Southeast Asia, with that same offset in every season.

Three levers run the Vietnam recovery: light, sleep timing and hydration. Start with pre-flight drift for Vietnam — 30–60 minutes per day toward Hanoi time. Hold the line in the air for Vietnam: water instead of wine.

Caffeine before noon only, and set the watch to Hanoi time, UTC+7. Each eastbound zone costs about one recovery day, each westbound zone about two-thirds of a day — so the London–Hanoi leg (eastbound, 7 hours) bills you about 7 days, while flying the opposite direction would cost only 4.7. Dry cabin air quietly drains you on the way to Vietnam; an extra 500 ml of water per 3 hours in the air keeps the Hanoi arrival day survivable.

Applied to this Southeast Asia trip: 7 hours east from London to Hanoi maps to about 7 reset days, so a Vietnam itinerary should front-load outdoor time on days one to 7.

Cool, dark and quiet wins in Vietnam: 16–20°C in the Hanoi room, a proper mask against dawn light, and no screens in the last hour before bed. A 10-minute warm shower an hour before bed speeds the core-temperature drop that starts sleep — a real head-start on the first jangled Vietnam nights in Hanoi.

Cap naps at 20–30 minutes and finish them by 3pm Hanoi time (UTC+7); anything longer steals the night that actually resets your clock to Vietnam. Practical baseline: lights out in a dark 16–20°C Hanoi room (19 m, UTC+7), and no evening alcohol for the first two nights while the Vietnam clock settles.