Jet Lag Calculator

How to use

1. 1Pick your home time zone and your destination time zone using the city picker or the All zones list.
2. 2Enter the departure date and time in home local time, and the arrival date and time in destination local time.
3. 3Enter your usual bedtime and wake time at home, and the target bedtime and wake time you want to keep at the destination.
4. 4Read the trip summary: time difference, direction (eastward or westward), and the estimated recovery in days.
5. 5Use the pre-trip schedule to shift your bedtime by up to one hour per night before you fly so you arrive partly adjusted.
6. 6Follow the post-arrival schedule for sleep, light-seeking, light-avoidance, optional melatonin, and caffeine cutoff times in destination local time.
7. 7Click Copy plan to save the full plan as plain text for a notes app, email, or printout.

About this tool

Jet Lag Calculator turns a trip into a day-by-day plan for adjusting your body clock to the destination time zone. You enter a home zone, a destination zone, the departure and arrival times (in their respective local time), and your usual bedtime and wake time at both ends. The tool then reports the signed time difference between the two zones, classifies the direction as eastward (advance the clock, generally harder) or westward (delay the clock, generally easier), and estimates how many days of recovery the shift is likely to need using the Waterhouse rule of thumb (about one day per hour eastward, about two-thirds of a day per hour westward). A pre-trip schedule walks back from departure and proposes a graduated bedtime shift of up to one hour per night for as many nights as the shift requires (capped at four), so you arrive partway adjusted instead of cold. A post-arrival schedule covers the first 2 to 7 destination days, and for each day shows the target sleep window, a bright-light-seeking window timed against the destination wake time (morning light to advance after eastward travel; evening light to delay after westward travel), a bright-light-avoidance window timed against the body clock minimum, an optional melatonin window for cases where a phase shift is desired, and a caffeine cutoff calibrated to roughly 8 hours before destination bedtime. All wall-clock times render in destination local time so you can act on them without converting in your head. A Copy plan button captures the full plan as plain text for a notes app, email, or printout. Useful for long-haul flyers heading from the US east coast to Europe or Asia, business travellers landing in time for a same-day meeting, athletes lining up training around a competition abroad, families travelling with kids who need a clear sleep schedule, and remote workers planning workcations across time zones. The schedule respects daylight saving time through the browser IANA database and works with any IANA time zone supported by your browser. Everything runs locally in your browser; nothing about your travel plan is uploaded. This is a planning aid based on published sleep and travel-medicine research, not medical advice.

Free to use. Works in your browser. No signup, no login.