Enter your departure city time zone, destination time zone, your usual wake time, and sleep quality to get a personalized jet lag severity score and recovery plan. The Jet Lag Calculator shows you how many time zones you're crossing, estimates your adjustment period, and gives you targeted tips on when to sleep, stay awake, and seek light exposure to sync your body clock faster.
Results
Jet Lag Severity Score
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Time Zones Crossed
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Estimated Recovery Time
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Your Body Clock Wake Time at Destination
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Severity Level
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Jet Lag Factors Breakdown
Results Table
Frequently Asked Questions
What is jet lag?
Jet lag is a temporary sleep disorder caused by crossing multiple time zones rapidly. Your internal body clock (circadian rhythm) remains set to your home time zone while your new environment operates on a different schedule, creating a mismatch that causes fatigue, disorientation, and disrupted sleep.
What are the symptoms of jet lag?
Common symptoms include daytime fatigue, difficulty concentrating, mood changes, disturbed sleep, digestive issues, and general malaise. Symptoms usually appear within a day of arrival and can last several days depending on how many time zones were crossed and your individual sensitivity.
Does direction of travel affect jet lag severity?
Yes — eastward travel is generally harder on the body than westward travel. Flying east requires your body to advance its clock (wake and sleep earlier), which is more difficult biologically than delaying it. As a rule, expect about 1 day of recovery per time zone when flying east and slightly less when flying west.
How does light exposure help with jet lag?
Light is the most powerful signal for resetting your circadian rhythm. Seeking bright light in the morning at your destination helps advance your body clock (useful for eastward travel), while evening light helps delay it (useful for westward travel). Avoiding light at the wrong times is equally important.
When is the best time to book a business meeting if I'm travelling for work?
Try to schedule important meetings after you've had at least one full night's sleep at your destination. If that's not possible, plan meetings during the late morning or early afternoon local time, which often overlaps with your peak alertness window from your home time zone.
Can melatonin help reduce jet lag?
Melatonin can be an effective aid when used correctly. Taking a low dose (0.5–3 mg) at your destination's target bedtime for the first few nights can help shift your body clock. Consult a healthcare professional before use, especially if you take other medications.
Does the length of my trip affect how I should manage jet lag?
Absolutely. For short trips of 1–3 days, it may actually be better to stay on your home time zone schedule rather than trying to adjust. For longer trips, it's worth investing effort in adapting to local time as fully as possible to maintain performance and well-being.
How much water should I drink on a long-haul flight to reduce jet lag?
Aim for at least 250 ml (8 oz) of water per hour of flight. Airplane cabin air is very dry — typically 10–20% humidity — which accelerates dehydration. Dehydration worsens fatigue and headaches, which amplify jet lag symptoms. Avoid alcohol and limit caffeine during the flight.