Jet Lag Recovery Calculator
Estimate your recovery time from jet lag after a long flight. This tool uses common rules of thumb to predict how many days it might take for your body's internal clock to adjust to a new time zone. The calculation considers the number of time zones you've crossed and the direction of your travel.
Estimated Jet Lag Recovery
After traveling East across 9 time zones
Estimated Full Recovery By
Wednesday, December 10, 2025
Estimated Recovery Duration
9 days
This is just an estimate. Recovery can be affected by factors like age, health, and sleep habits.
Example Jet Lag Recovery
This example follows a typical long-haul flight to demonstrate how the recovery estimate is calculated from start to finish.
Sample Flight Details
- Traveler: Jordan
- Departure: America/New York on November 1, 2024
- Arrival: Asia/Tokyo
How the Estimate is Built
- Compare time zones: The departure offset of -4 hours and arrival offset of 9 hours differ by 11 time zones after adjusting for the international date line.
- Determine travel direction: Because the arrival offset is larger, the trip moves eastward, making it a(n) east journey.
- Apply the recovery rule: Traveling east uses the 1 day per time zone rule, which results in 11 recovery days.
Adding those recovery days to the departure date suggests Jordan should feel adjusted by November 12, 2024.
How Jet Lag Recovery is Estimated
The Rule of Thumb
This calculator uses a common and widely accepted rule of thumb for estimating jet lag recovery. The core idea is that your body's internal clock (circadian rhythm) can only adjust so much each day.
- Determine Time Zones Crossed: First, the calculator finds the difference in UTC offset between your departure and arrival time zones. For example, New York (UTC-4 in summer) to London (UTC+1) is a 5-hour difference.
- Determine Direction of Travel: It identifies whether you traveled East (advancing time) or West (reversing time).
- Apply Recovery Rate:
- Traveling East: The body finds it harder to advance its clock. The rule is approximately 1 day of recovery per time zone crossed.
- Traveling West: It's easier for the body to delay its clock. The rule is approximately 2/3 of a day of recovery per time zone crossed.
- Calculate End Date: The calculated number of recovery days is added to your departure date to estimate when you'll feel fully adjusted.
Example From Your Trip
- From: UTC
- To: Asia/Tokyo
- Direction: East
- Time Zones Crossed: 9
Because you are traveling east across 9 time zones, the calculator estimated it will take 9 days for your body to fully adjust. Adding this to your departure date gives an estimated full recovery by December 10, 2025.