Jet Lag Planner
Estimate how many days you may need to adjust after crossing time zones east or west, and how many hours to shift your schedule each day. A rule-of-thumb wellness aid.
Results
Adjust over (days)
Shift per day (hours)
- Tip
- Shift bedtime earlier gradually; morning light helps eastbound recovery.
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Educational estimates · not financial advice · free, no signup
Formula / how it works
East: ~1 day per zone. West: ~0.75 day per zone. Shift/day = zones ÷ adjust days. Rule-of-thumb wellness guide only.
Detailed guide
What it is, how to use it, how to read the numbers, common mistakes, a worked example, formulas, and FAQs.
What this calculator is
Jet lag happens when your internal clock is out of step with local time after a fast trip across time zones. A common rule of thumb says recovery takes about one day for each zone crossed when flying east and a little less when flying west, because most people find it easier to stay up later than to fall asleep earlier. This planner uses that rule to estimate the days of adjustment and the hours you could shift each day if you begin adapting before and during the trip. It is a simple planning aid. Individual response varies with age, sleep habits, light exposure and the flight itself, and anyone with a medical condition should ask a clinician for advice.
When to use / who it helps
- You are planning a trip across several time zones and want to estimate adjustment time.
- You want to decide whether to start shifting your sleep before departure.
- You are scheduling important meetings after arrival.
- You are comparing eastbound and westbound travel.
- You want an idea of how many hours to shift each day.
How to use
Steps
- Enter the number of time zones crossed.
- Choose the direction, eastbound or westbound.
- Read the estimated adjustment days.
- Read the shift per day in hours.
- Plan sleep and light exposure to move gradually towards the destination time.
- Treat the numbers as a guide and adapt to how you feel.
How to interpret results
- Eastbound travel usually takes longer to adjust to than westbound.
- Shift per day is the number of zones divided by the days you allow.
- Morning light tends to advance the body clock, while evening light delays it.
- Individual differences are large, and the estimate is approximate.
- Short trips of one or two days may not be worth fully adjusting.
Common mistakes & gotchas
- Expecting the rule of thumb to be exact.
- Counting hours of flight time instead of time zones crossed.
- Scheduling critical tasks on the first day after a long eastbound flight.
- Ignoring hydration, sleep opportunity and alcohol and caffeine timing.
- Using the planner as medical advice.
Worked example
Worked example — 6 time zones east
- Eastbound at about one day per zone: 6 zones × 1 = 6 days of adjustment.
- Daily shift: 6 ÷ 6 = 1 hour per day.
- For the same 6 zones westbound: 6 × 0.75 = 4.5 days.
- Westbound daily shift: 6 ÷ 4.5 ≈ 1.33 hours per day.
Result: Six zones east: about 6 days and 1 hour per day; six zones west: about 4.5 days.
To load the form's own demo values, tap Try example above the Calculate button.
How to calculate / formula
East: ~1 day per zone. West: ~0.75 day per zone. Shift/day = zones ÷ adjust days. Rule-of-thumb wellness guide only.
Frequently asked questions
How long does jet lag last?
A common rule of thumb is about a day per zone eastbound and a little less westbound, but it varies by person.
Is eastbound worse than westbound?
Many people find eastbound harder because it requires going to sleep earlier than the body wants.
Should I shift my sleep before I travel?
Some travellers shift by an hour or so a day before leaving. It can help but is optional.
Does light exposure matter?
Yes, light is a strong cue for the body clock. Timing it appropriately can speed adjustment.
Is this medical advice?
No. For persistent problems or medical conditions, consult a clinician.
Do short trips need adjustment?
Often not. Staying on home time can be easier for very short trips.
For education and personal goal-setting only — not medical advice, diagnosis, or treatment. Talk to a qualified clinician about your health. Full disclaimer