🕐 TimeFYI

Jet Lag Calculator

Estimate jet lag recovery time for any flight route. Calculates adaptation days based on timezone difference and travel direction, with personalized tips.

Calculator

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How to Use

  1. 1
    Select departure zone

    Choose the time zone of your departure city from the dropdown.

  2. 2
    Select arrival zone

    Choose the time zone of your destination city.

  3. 3
    View recovery estimate

    See the estimated recovery time, direction of travel, and personalized adaptation tips.

About

Jet lag, medically known as desynchronosis, occurs when rapid travel across time zones disrupts the body's circadian rhythm. The suprachiasmatic nucleus (SCN) in the hypothalamus serves as the master biological clock, synchronized primarily by light exposure.

Research from the Mayo Clinic indicates that the body adjusts approximately 1 to 1.5 time zones per day, with eastward travel being consistently more difficult. The asymmetry exists because the human circadian period averages about 24.2 hours — slightly longer than a solar day — making it easier to delay sleep than advance it.

Modern jet lag management focuses on strategic light exposure: bright morning light to advance the clock (for eastward travel) and bright evening light to delay it (for westward travel). The timing of meals and physical activity also plays a role in circadian resetting.

FAQ

Why is eastward travel harder?
Eastward travel shortens your day, requiring you to fall asleep earlier. The body's circadian clock naturally runs slightly longer than 24 hours, making it easier to stay up late (westward) than go to bed early (eastward).
How accurate is the recovery estimate?
The estimate uses the general rule of 1 day per time zone crossed for westward travel and 1.5 days per zone for eastward. Individual results vary based on age, health, and light exposure.
Does melatonin help with jet lag?
Studies show that melatonin taken at the destination's bedtime can help reset circadian rhythm. Typical doses are 0.5-5mg, taken 30 minutes before desired sleep time. Consult a doctor before use.
What is the best way to prevent jet lag?
Start shifting your schedule 2-3 days before departure. Seek bright light in the morning for westward travel and in the evening for eastward travel. Stay hydrated and avoid alcohol on the flight.