Calculator Inputs
Example Data Table
| Route | UTC Shift | Flight Hours | Direction | Likely Recovery | Best Light Focus |
|---|---|---|---|---|---|
| London to Dubai | +4 hours | 7.1 | Eastward | 3 to 4 days | Morning light |
| New York to London | +5 hours | 6.8 | Eastward | 4 to 5 days | Morning light |
| Tokyo to Los Angeles | -8 hours | 10.2 | Westward | 4 to 6 days | Evening light |
| Sydney to Singapore | -3 hours | 8.0 | Westward | 2 to 3 days | Late day light |
Formula Used
The calculator estimates jet lag from time zone displacement, flight duration, sleep debt, travel direction, age group, sleep quality, cabin comfort, caffeine, alcohol, hydration, meal timing, and daylight access.
Time shift: Arrival UTC offset − departure UTC offset.
Flight duration: Arrival UTC time − departure UTC time.
Sleep debt: Normal sleep need − actual sleep before and during flight.
Risk score: Shift load + flight load + sleep load + lifestyle modifiers.
Adjustment days: Eastward shifts usually adjust slower than westward shifts.
The result is an estimate for planning. It does not replace medical advice. Travelers with health concerns should speak with a qualified professional.
How to Use This Calculator
- Enter your departure and arrival cities.
- Add local departure and arrival date times.
- Enter each city UTC offset.
- Choose sleep, cabin, light, meal, and hydration factors.
- Press the calculate button.
- Review your score, recovery days, and light timing plan.
- Download the result as a CSV or PDF report.
BA Jet Lag Planning Guide
Why Jet Lag Happens
Jet lag happens when your inner clock disagrees with local time. The body still expects sleep, meals, alertness, and temperature changes from the old time zone. Long flights can also add dehydration, poor sleep, heavy meals, and cabin fatigue. These factors can make a simple time change feel stronger.
Why Direction Matters
Eastward travel often feels harder. You must sleep earlier than usual. That can be difficult for evening types. Westward travel often feels easier because many people can stay awake later. Still, large westward shifts can cause early waking, low energy, and afternoon sleepiness.
How Light Controls Recovery
Light is the strongest timing signal for the body clock. Morning light usually helps advance the clock. Evening light usually delays it. This is why the calculator gives a light window. Correct light exposure can reduce confusion after arrival. Poor timing can delay recovery.
Sleep and Food Timing
Sleep debt increases jet lag. Try to avoid starting a trip tired. Keep naps short after landing. Eat by destination time as soon as practical. Use caffeine carefully. Stop it several hours before your target bedtime. Drink water steadily during travel.
Using the Result
The score helps compare trip difficulty. A low score means light planning may be enough. A high score needs stronger preparation. Move bedtime before departure when possible. Protect the first local night of sleep. Plan demanding work after your estimated recovery window when your schedule allows.
FAQs
1. What does BA mean in this calculator?
BA refers to body adjustment. The calculator estimates how your body clock may adjust after crossing time zones.
2. Is eastward travel always harder?
Eastward travel is often harder because it asks the body to sleep earlier. Personal chronotype and sleep habits also matter.
3. Why does flight duration affect the score?
Long flights can reduce sleep, movement, hydration, and meal regularity. These factors can increase fatigue after arrival.
4. How accurate are the recovery days?
They are planning estimates. Real recovery depends on health, sleep quality, daylight exposure, stress, and your arrival schedule.
5. Should I nap after landing?
A short nap can help severe fatigue. Keep it near 20 minutes and avoid late afternoon naps when possible.
6. Why does the calculator ask for caffeine?
Caffeine can improve alertness, but late use can delay sleep. The calculator gives a destination time cutoff.
7. Can meal timing reduce jet lag?
Meal timing can support adjustment. Eating by destination time helps reinforce the new daily rhythm.
8. Can I download the result?
Yes. After calculation, use the CSV or PDF buttons shown above the form.