Jet Lag Recovery Calculator
Build a direction-aware pre-trip sleep shift and destination adaptation plan from CDC averages. Inputs stay in your browser.
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.
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.
Sources & scope
The calculation guide and this source trail show what the result means, where the rule came from and when it was last reviewed. This is source-and-calculation QA, not a claim of medical, legal, tax or other professional review; time-sensitive decisions still belong with the linked authority.
A visible path from input to answer.
Build a direction-aware pre-trip sleep shift and destination adaptation plan from CDC averages. The page keeps the calculation scope and its limits beside the result so the output can be checked, copied or revisited.
- Read the record. The calculator uses Arrival date, Time zones crossed, Travel direction, Days at destination and Days available to shift before travel and 2 additional fields supplied in the form.
- Apply the scope. It applies the Global travel-health planning — CDC Yellow Book directional averages reference and the explicit date, unit and counting conventions shown in the result.
- Expose the checkpoints. Intermediate rows, warnings and timeline events stay visible; the emphasized row identifies the primary checkpoint when one exists.
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.
- Pre-trip sleep target19:00 bedtime · 04:00 wake
- Estimated residual adaptation5 days
Calculation purpose: Build a direction-aware pre-trip sleep shift and destination adaptation plan from CDC averages. This is a general planning reference; local conditions, product instructions or personal records can override the estimate.
Calendar inputs use plain year-month-day semantics. Leap days, month ends, date-pair order and unsupported dates are checked before the result is shown.
Rule set 2.0.0 · Last reviewed 2026-08-20 · Next review due 2027-02-20. The source panel below contains the linked evidence.
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.