Jet Lag Recovery Calculator
How long jet lag will last and how to adjust.
Reviewed by James Whitfield · How we check our maths
Your values
ⓘ Live results
Results
- Estimated recovery
- 11.9 days
- Direction difficulty
- Harder — you must sleep earlier
- Pre-trip shift per day
- 2.7 hours
- Best light exposure
- Morning light on arrival
- Avoid light
- Late evening
| Tactic | Effect |
|---|---|
| Shift bedtime before travel | Cuts recovery by 1–2 days |
| Time light exposure | Strongest single zeitgeber |
| Skip alcohol in flight | Protects sleep quality |
| Eat on destination schedule | Aligns peripheral clocks |
Quick answer
The body re-syncs about one time zone per day travelling west and roughly two-thirds of that going east.
The formula
Days ≈ zones ÷ 1.0 (west) or zones ÷ 0.67 (east)
Worked example
Worked example
Using the values the calculator loads with.
Inputs
- Time zones crossed8
- DirectionEastward
- Days before departure to prepare3
Result
- Estimated recovery11.9 days
- Direction difficultyHarder — you must sleep earlier
- Pre-trip shift per day2.7 hours
- Best light exposureMorning light on arrival
- Avoid lightLate evening
How to use the Jet Lag Recovery Calculator
- 1Enter how many time zones you're crossing.
- 2Choose the direction of travel.
- 3Set how many days you can prepare beforehand.
Frequently asked questions
Why is eastward travel worse?
Your natural body clock runs slightly longer than 24 hours, so delaying sleep is easier than advancing it.
Does melatonin help?
Low doses timed correctly can advance the clock for eastward travel; timing matters far more than dose.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error