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How to Calculate Jet Lag

What is Jet Lag?

Jet lag is a temporary circadian rhythm disruption from rapid travel across time zones. The internal clock — regulated by light — takes time to sync with the new local time.

Formula

Recovery time (days) ≈ Time zones crossed × 0.5–1.0 | Eastward: "gain sleep"; westward: "lose sleep"

Step-by-Step Guide

  1. 1Typical recovery: ~1 day per time zone crossed
  2. 2Eastward travel (phase advance) is harder than westward
  3. 3Melatonin at local bedtime helps reset the clock
  4. 4Morning light exposure at destination speeds adaptation

Worked Examples

Input
London → Tokyo (9 time zones east)
Result
Recovery ≈ 9–12 days; take 0.5–5mg melatonin at local bedtime for 5 nights

Frequently Asked Questions

What is Jet Lag?

Jet lag is a temporary circadian rhythm disruption from rapid travel across time zones. The internal clock — regulated by light — takes time to sync with the new local time

How accurate is the Jet Lag calculator?

The calculator uses the standard published formula for jet lag. Results are accurate to the precision of the inputs you provide. For financial, medical, or legal decisions, always verify with a qualified professional.

What units does the Jet Lag calculator use?

This calculator works with inches. You can enter values in the units shown — the calculator handles all conversions internally.

What formula does the Jet Lag calculator use?

The calculator applies the standard formula for this type of calculation. See the 'How It Works' steps above for the detailed formula breakdown.

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