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jetlag.info

Chronobiology for travellers

Understand jet lag.
Arrive rested.

Your inner rhythm, your route, your plan. See how strongly the time shift hits — and when to seek or avoid light.

jetlag.info offers general orientation for adjusting your sleep–wake rhythm — not a medical diagnosis or treatment. The jet-lag score is a transparent heuristic, not a validated measurement. For health questions, consult a medical professional.

Jet lag calculator

Your personal adjustment plan in ten seconds.

Interactive calculation with the full airport search loads with JavaScript.

Popular calculators

Six tools, one goal: arrive rested

Every tool runs on your real route and sleep window — no blanket tips.

Jet lag calculatorTime zones, direction and the estimated adjustment time for your route.Time differenceWhat time is it at your destination — and how big is the jump?Body clockWhere your inner clock sits versus local time at the destination.Light plannerWhen to seek light and when to avoid it — the strongest zeitgeber, timed right.East / westEastbound or westbound? See which direction hits you harder.Flight sleep plannerSleep or stay awake? The ideal window for your flight.

Knowledge

Understand first, then adjust

Short, well-grounded explanations — without medical jargon.

What is jet lag?

Why your body needs days to adjust to a new time zone — and what melatonin and cortisol have to do with it.

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East or west?

Eastbound flights are harder for most people because the day is shortened. Westbound adjustment is often easier.

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How long does jet lag last?

A rough rule of thumb: about one day of adjustment per time zone crossed. An estimate, not a law of nature.

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Light as a zeitgeber

Light is the strongest cue for your inner clock. Applied at the right time, it noticeably speeds up the switch.

Read article →

Route guides

Popular routes, worked through

Frankfurt → Tokyo+7 time zonesEastbound · harder Frankfurt → Los Angeles−9 time zonesWestbound · easier London → New York−5 time zonesWestbound · easier Frankfurt → Singapore+6 time zonesEastbound · harder

Jet lag, explained — and calculated

jetlag.info turns the science of your body clock into a plan you can act on. Every calculator runs on your real route and sleep window: enter where you fly from and to, and get a transparent jet‑lag score, the direction and size of the time shift, an adjustment estimate in days, and timed‑light windows to reset faster. The tools share one engine, so you enter your trip once and it follows you from the jet lag calculator to the light planner and the day‑by‑day planner. Prefer the background first? The science of jet lag and the basics explain the circadian rhythm, melatonin and light in plain English.

Orientation, not diagnosis

jetlag.info gives general orientation for adjusting your sleep–wake rhythm — not a medical diagnosis or treatment. For health questions, consult a medical professional.