Jet Lag Calculator

Plan your itinerary around your body clock. Jet lag severity depends on time zones crossed and flight duration. Minimal (1-2 zones) means you'll feel fine by afternoon — just stay hydrated and get outside in daylight. Mild (3-4 zones) takes 2-3 days to adjust — plan light activities for your first two days. Moderate (5-7 zones) needs 4-6 days of recovery — avoid important meetings and heavy lifting. Severe (8-10 zones) requires a full week — consider melatonin, gradual schedule shifts before departure, and morning sunlight at your destination. Extreme (11+ zones) is the worst case — you might need 10-14 days to feel normal. Eastward travel is harder than westward because it forces you to sleep earlier.

How to Use This Tool

Enter the number of time zones you crossed.
Enter your flight duration.
Get estimated recovery time and fatigue level.

The Formula

Approx. 1 day recovery per time zone crossed, plus extra for flights over 6 hours.

Why It Matters

You fly from New York to Tokyo, crossing 13 time zones eastward. Expect severe jet lag with approximately 13 days to recover. Start shifting your schedule 3 days before departure to ease the transition.