โœˆ๏ธ Travel

Sleep Calculator for Long Haul Flights, Beat Jet Lag Using Sleep Science

By BedtimeCalc Sleep Science Team ยท ยท โฑ 7 min read ยท ๐Ÿ”ฌ Evidence based

A London to Tokyo flight crosses 9 time zones. A New York to Dubai flight crosses 9. Your circadian clock can only shift 1, 1.5 hours per day, meaning full adjustment takes a week without intervention. This calculator tells you when to sleep on the plane and what to do on arrival for the fastest possible clock reset.

๐Ÿ›๏ธ Harvard Sleep Medicine aligned
๐Ÿ“‹ NSF 2022 guidelines
๐Ÿ”ฌ Peer reviewed sources
โœ… Reviewed April
ScenarioBedtimeWake UpCyclesDurationStatus
London โ†’ NYC (5h west, 7h flight)11:30 PM7:00 AM57.5 hrsOptimal
London โ†’ Tokyo (9h east, 12h flight)3:00 PM7:00 AM34.5 hrsMinimum
NYC โ†’ Dubai (8h east, 12h flight)10:30 PM6:30 AM57 hrsGood
Sydney โ†’ London (11h west, 24h trip)10:30 PM7:00 AM57.5 hrsOptimal
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East vs. West: Why Direction Matters

Your circadian clock advances (shifts earlier) at maximum 1 hour per day and delays (shifts later) at maximum 1.5 hours per day. This means westward travel is biologically easier, you're essentially staying up a bit later. Eastward travel requires advancing your clock, which is harder. A London to Tokyo flight (9 hours east) takes approximately 9 days to fully adjust without light intervention, or 4, 5 days with the right protocol.

โœˆ๏ธ The Flight Sleep Strategy

The goal on a long haul flight is not maximum sleep, it's sleep timed to match your destination's night. Sleeping during your destination's daylight hours locks in the wrong circadian timing. Use a calculator to find when it will be 10 PM, 6 AM at your destination, and try to sleep only during that window.

Light Therapy: The Most Powerful Jet Lag Tool

Light is the primary signal that resets the circadian clock. On arrival at your eastward destination: seek bright morning light (outdoor preferred) during the hours that correspond to 8, 10 AM at your destination. Avoid bright light during hours that correspond to late evening at your destination. This single protocol, applied consistently for 3 days, reduces east bound jet lag adjustment time by approximately 50%.

Melatonin Timing for Eastward Flights

0.5mg melatonin taken at 10 PM destination time for 3 nights after an eastward arrival accelerates clock advancement. This is the scientifically validated dose, the 5, 10mg products in pharmacies are 10, 20ร— higher than the physiologically effective amount. The melatonin doesn't put you to sleep; it signals to your clock that it's night at your destination, accelerating the adjustment.

๐Ÿ”„ Long Haul Flight Recovery Protocol
  • 1Pre flight: shift your bedtime 30 minutes earlier per night for 3 nights before eastward travel.
  • 2On the flight: use a sleep mask and earplugs, quality sleep on planes is possible but requires blocking light and sound.
  • 3Arrival: stay awake until local bedtime (10 PM) on day 1, no matter what.
  • 4Arrival days 1, 3: get 30 minutes of outdoor light before 10 AM at your destination.
  • 5Melatonin: 0.5mg at 10 PM destination time for 3 nights after arrival (eastward only).

๐ŸŒ™ Calculate Your Flight Sleep Schedule

Enter your departure and destination time zones for your in flight sleep timing.

Calculate My Bedtime โ†’
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๐ŸŒ™
BedtimeCalc Sleep Science Team
Our recommendations are grounded in peer reviewed sleep research, including landmark work by Kleitman & Aserinsky (1953) and National Sleep Foundation guidelines. Every page is reviewed before publication and updated when new research emerges.
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Frequently Asked Questions

Yes, but timed to your destination's night. Sleeping during your destination's daytime locks in the wrong clock position. Use a sleep mask and earplugs, and try to sleep during the 8 hour window that corresponds to 10 PM, 6 AM at your destination.

Without intervention: approximately 1 day per time zone crossed for eastward travel. With morning light therapy and correctly timed melatonin: roughly half that, 4, 5 days for a 9 hour time zone difference.

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