Jet Lag Recovery Calculator
Estimate days to recover from jet lag.
Results update as you type.
How it works
Jet lag happens when rapid travel across time zones desynchronizes your internal body clock from local time, and this calculator estimates how long recovery takes. You enter the number of time zones crossed, and it returns the estimated recovery time and a suggested number of days to pre-adjust before your trip. The estimate is based on the well-known guideline that the body's circadian rhythm shifts by roughly one time zone per day, or a bit less, so crossing many zones can take the better part of a week to fully adjust. Direction matters in reality: traveling east (advancing your clock) is generally harder to adapt to than traveling west (delaying it), because it is easier for the body to stay up later than to fall asleep earlier — this calculator gives a general estimate, so add a bit for eastward trips. You can shorten jet lag by pre-adjusting your sleep schedule toward the destination's time in the days before departure, getting bright light at the right times, staying hydrated, adjusting to local meal and sleep times on arrival, and using short strategic naps. The suggested pre-adjustment days give a starting point for shifting your schedule gradually. Understanding your recovery timeline helps you plan important activities for after you have adjusted. Enter the time zones crossed to estimate recovery.
Recovery days ≈ time zones crossed × 2/3
A common rule of thumb is that the body adjusts to roughly one time zone every day to day-and-a-half, so recovery takes about two-thirds of a day per zone crossed. The suggested pre-adjustment is about half the zones, spent shifting your schedule before departure.
Source:Circadian adjustment guidelines
We review all our tools from time to time to ensure accuracy.
Worked example
How to use this calculator
- 1
Enter your values
Enter time zones crossed.
- 2
Adjust the options
Fine-tune any options to match your situation.
- 3
Read your result
Estimated recovery time updates instantly as you type — no button to press.
Frequently asked questions
How long does it take to recover from jet lag?
A common rule is that the body adjusts about one time zone per day, so recovery takes roughly two-thirds to one day per zone crossed. Crossing eight zones might take around six days to fully adjust. Individual recovery varies with age, health, direction of travel, and how well you manage light and sleep.
Is eastward or westward travel worse for jet lag?
Eastward travel is generally harder. Flying east advances your clock, requiring you to fall asleep and wake earlier, which the body resists because our natural rhythm runs slightly longer than 24 hours. Flying west delays your clock, letting you stay up later, which is easier to adapt to. So expect somewhat longer recovery on eastbound trips.
How can I reduce jet lag?
Start shifting your sleep schedule toward the destination time a few days before departure, seek or avoid bright light at strategic times, stay hydrated and limit alcohol and caffeine, and adopt local meal and sleep times immediately on arrival. Short naps can help, and getting morning sunlight at your destination helps reset your body clock faster.
What causes jet lag?
Jet lag results from a mismatch between your internal circadian clock, which governs sleep, alertness, digestion, and hormones, and the new local time after crossing time zones quickly. Your body clock is still set to home time, so you feel sleepy, hungry, or alert at the wrong times until it gradually resynchronizes with the destination's day-night cycle.
Should I pre-adjust before traveling?
Pre-adjusting can meaningfully reduce jet lag. In the days before departure, gradually shift your bedtime and wake time toward the destination's schedule — earlier for eastward travel, later for westward. Even partial adjustment before you leave means your body has less of a gap to close on arrival, so you recover faster and feel better sooner.