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CalcSpan/Jet lag, passports and travel rules/Jet Lag Circadian Adaptation Schedule
Jet lag, passports and travel rules · Calculator

Jet Lag Recovery Calculator
without the guesswork.

Jet Lag Circadian Adaptation Schedule — Build a direction-aware pre-trip sleep shift and destination adaptation plan from CDC averages. Uses a focused calculator with visible assumptions. Inputs stay in your browser.

Reference toolJet Lag Circadian Adaptation ScheduleBuild a direction-aware pre-trip sleep shift and destination adaptation plan from CDC averages. Inputs stay in your browser.
Reference calculation
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Fri, Sep 4, 2026

Plain-date semantics · start date is not counted unless the result explicitly says inclusive.

Your result
About 5 destination days after pre-shifting

CDC's average directional rates suggest about 8 days without preparation; the pre-trip plan reduces the remaining shift but cannot guarantee symptom-free travel.

Arrival dateSep 4, 2026
DirectionEastward — advance the body clock
Average adaptation rate1 hour per dayCDC population average, not an individual promise
Pre-trip sleep target19:00 bedtime · 04:00 wake3 hours shifted before departure
Destination light emphasisMorning light after 07:00; reduce late-evening light
Estimated natural adaptation8 days
Estimated residual adaptation5 days7-day stay
Timeline
Sep 1, 2026Pre-trip shift day 1Move sleep about 1 hour earlier
Sep 2, 2026Pre-trip shift day 2Move sleep about 1 hour earlier
Sep 3, 2026Pre-trip shift day 3Move sleep about 1 hour earlier
Sep 4, 2026Destination adaptation day 1
Sep 5, 2026Destination adaptation day 2
Sep 6, 2026Destination adaptation day 3
Sep 7, 2026Destination adaptation day 4
Sep 8, 2026Destination adaptation day 5
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Read before relying

Context matters.

  • Timed light can shift the clock in the wrong direction if used at the wrong biological time; this page gives directional planning, not a clinical light prescription.
  • Stay on destination meal and sleep times, seek daylight, avoid long daytime naps, stay hydrated and limit excess alcohol as described by CDC guidance.
  • Discuss melatonin, sedatives, stimulants, pregnancy, sleep disorders and medication interactions with a clinician or pharmacist.
Rule set 2.0.0

Sources & scope

Verified

This page shows the source trail, jurisdiction and review date alongside the result. Always confirm time-sensitive rules with the linked authority.

CalcSpanPlain-date calculation method and input semanticsRetrieved 2026-08-20CDC Yellow BookJet Lag DisorderRetrieved 2026-08-20
JurisdictionGlobal travel-health planning — CDC Yellow Book directional averages
Review date2027-02-21
PrivacyNo input upload
Questions answered

What to know before using the result.

Why does eastward travel usually take longer?

CDC notes that most people shift later more easily than earlier, with average adaptation around 1.5 hours per day westward and 1 hour per day eastward.

Should I adapt for a very short trip?

For a trip under about two days, CDC guidance notes that keeping a home-base schedule can be practical when obligations and safety allow.

Does this calculator prescribe melatonin?

No. Mistimed melatonin or light can shift the clock the wrong way, and medication or pregnancy considerations require a clinician or pharmacist.

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