What is jet lag and what causes it?

Jet lag (desynchronosis) is a temporary sleep disorder that occurs when your internal body clock (circadian rhythm) is out of sync with the time zone you've traveled to. Your body's circadian rhythm regulates sleep-wake cycles, hormone release, body temperature, and other functions based on your home time zone. When you rapidly cross multiple time zones, your body needs time to adjust to the new schedule.

How long does jet lag typically last?

A general rule of thumb is that it takes about one day to recover for each time zone crossed. So if you travel across 6 time zones, expect about 6 days for full adjustment. However, this varies by individual and direction - eastward travel typically causes worse jet lag than westward travel because it's easier to delay sleep (going west) than to advance it (going east).

Why is eastward travel harder on jet lag than westward?

Traveling east requires advancing your sleep schedule (going to bed earlier), which is more difficult than delaying it. Most people naturally have a circadian rhythm slightly longer than 24 hours, making it easier to stay up later (westward travel) than to fall asleep earlier (eastward travel). Studies show eastward jet lag recovery takes about 50% longer than westward recovery.

What are the symptoms of jet lag?

Common jet lag symptoms include: difficulty falling asleep or staying asleep, excessive daytime fatigue, difficulty concentrating, mood changes and irritability, digestive problems, reduced physical and mental performance, and general feeling of being unwell. Symptoms are typically worse when more time zones are crossed and when traveling eastward.

How can I minimize jet lag?

Strategies to reduce jet lag: gradually adjust sleep schedule a few days before departure, stay hydrated during flight, avoid alcohol and caffeine, get sunlight exposure at appropriate times in your destination, consider melatonin supplements (consult a doctor), stay active during destination daytime, and try to sleep on the plane if it's nighttime at your destination. For trips under 3 days, some travelers prefer staying on home time.

Date & Time

Jet Lag Calculator

Estimate recovery time for jet lag based on time zones crossed.

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How to Use This Calculator

Enter Your Travel Details

Input your departure location (city or time zone), arrival destination, and travel direction (eastward or westward). The calculator needs this information to determine how many time zones you're crossing and in which direction, as both factors affect recovery time.

Calculate Recovery Time

Click calculate to see your estimated jet lag recovery period. The calculator uses the general rule of approximately one day per time zone crossed, with adjustments for travel direction (eastward travel typically adds 50% more recovery time).

Review Recommendations

Read the personalized suggestions for minimizing jet lag based on your specific route. This may include optimal times for light exposure, sleep schedule adjustment strategies before departure, and tips for your first few days at the destination.