MundoKit

Jet lag sleep-shift planner

Choose a baseline bedtime, sleep duration and daily shift before your trip. Get a printable schedule showing the same sleep window in both time zones.

JavaScript is required for time-zone conversion. Your schedule inputs stay in this browser.

This is general information, not medical advice.

How it works

The CDC Yellow Book gives examples of shifting sleep 60 minutes earlier for eastward travel or later for westward travel over the preceding 2–3 days. Select a published example or keep custom settings; these examples are not individualized prescriptions. This worksheet translates an adjustment you select; it does not estimate circadian phase, prescribe a shift, predict recovery or generate medication and light-exposure instructions.

Local bedtime on day n = baseline date/time + n calendar days ± n × chosen minutes Wake instant = bedtime instant + chosen elapsed sleep duration

Day 0 is your unchanged baseline. Later rows apply the cumulative shift in the origin’s local clock. Both columns then show the same instants using IANA time zones through Intl.DateTimeFormat. Full dates make midnight and date-line changes visible. Destination times are equivalents, not target bedtimes after arrival.

Bedtime is entered to whole minutes; sleep duration must also resolve to whole minutes. Whole-minute durations are normalized to integer minutes after allowing only floating-point representation noise. No other intermediate rounding is applied. Daylight-saving changes may alter the displayed wake time while elapsed sleep opportunity stays constant. A bedtime that is skipped or occurs twice during a clock change is rejected; choose an unambiguous time. Time-zone results depend on your browser’s rule database. Worksheet limits are not clinical recommendations.

Worked examples

Three earlier bedtimes before London to Tokyo

Start at 23:00 in London on November 14, 2026, with 8 hours of sleep and a chosen 30-minute daily advance. On day 3, bedtime is 21:30 on November 17 and wake time is 05:30 on November 18 in London. Tokyo equivalents are 06:30 and 14:30 on November 18. The chosen total shift is 90 minutes earlier.

A later bedtime crosses midnight

Start at 23:30 in New York on November 14, 2026. Choose one day shifting 60 minutes later and 8 hours of sleep. Day 1 bedtime becomes 00:30 on November 16 in New York, equivalent to 21:30 on November 15 in Los Angeles. New York wake time is 08:30 on November 16.

Frequently asked questions

Will this tell me how long jet lag will last?
No. It displays a chosen schedule. Biological adaptation depends on factors this worksheet does not measure.
Does the planner decide earlier or later for me?
You can select a CDC eastward or westward example for two or three adjustment days, or choose your own direction and daily amount. Destination columns translate the schedule but do not recommend when to sleep there.
Why use IANA zones instead of UTC offsets?
Names such as America/New_York let the browser apply date-specific offset rules, including daylight-saving changes and fractional-hour zones.
What happens when clocks change during sleep?
The selected sleep duration is elapsed time. For example, an 8-hour interval can span a different number of local clock hours. Ambiguous or nonexistent bedtimes are rejected.
Can I print or save my schedule?
Use Print schedule and your browser’s printer or PDF option. Inputs are not saved automatically.

Sources

Last reviewed 2026-11-14; next review due by 2027-01-15. The method is written out above so you can check our math.