Flying across time zones for work? This free jet lag planner turns your route, flight times and usual sleep hours into a day-by-day plan: when to seek and avoid bright light, when to sleep, nap, have coffee, eat and fit in a short hotel-room workout, based on CDC and sleep-research guidance.
On the plane
- Drink water regularly; dry cabin air and long flights make it easy to under-drink, and dehydration can make jet lag feel worse.
- Go easy on alcohol. It can help you fall asleep, but it breaks up your sleep, which is the opposite of what you need.
- An eye mask and earplugs make sleeping at the right time much easier.
What about melatonin?
Some travellers use melatonin for jet lag, and sleep-medicine guidelines rate correctly timed melatonin as helpful. Rules differ by country: it is sold as a supplement in the US but needs a prescription in the UK and in several EU countries. The CDC notes that 0.5 to 1 mg is often enough to shift the body clock and that high doses (over 5 mg) are not recommended. Timing matters, because at the wrong time it can shift your clock the wrong way, so ask your doctor or pharmacist before you use it, especially if you take other medicines.
Flying home? Run the planner again with your return flight.
How this jet lag planner works
Your body clock does not reset when the plane lands. It runs on its own roughly 24-hour rhythm, and its lowest point, the core body temperature minimum, usually falls about 2 to 4 hours before your normal wake time. Bright light in the hours after that low point moves your clock earlier (a phase advance); bright light in the hours before it moves your clock later (a phase delay). Light at the wrong time can push your clock the wrong way, which is why the plan tells you when to avoid light as well as when to seek it.
The planner works out the real time difference for your travel dates using your browser’s time zone data, so daylight saving changes and the International Date Line are handled for you. Then it picks a direction:
- Flying east (destination clock ahead) means your clock must run earlier. The plan uses morning light at body-clock time and avoids light before it. People adjust about 1 hour per day after eastward flights.
- Flying west means your clock must run later. The plan uses evening light and keeps early-morning light low. People adjust about 1.5 hours per day after westward flights.
- Eight or more time zones east (for example London to Sydney): the plan shifts your clock later instead, because after big eastward trips the clock often shifts that way anyway and delays are easier.
- Three hours or less: you get a minimal plan. Switch to local time and use a little well-timed light.
- Short trips under 3 days: the plan keeps you close to home time, with a compromise sleep window, because there is little point adjusting for a day or two and then adjusting back.
Shifting your bedtime and wake time by 1 hour a day for 2 to 3 days before you fly, with light timed to match, gives you a head start; even 1 or 2 days helps. On arrival, the plan sets a sleep window within 2 hours of your usual local bedtime so you can still work normal hours while your clock catches up.
Jet lag tips for business travellers
- Light is the main tool. Outdoor daylight is far brighter than office or hotel lighting, even on a cloudy day. When the plan says avoid light, wear dark sunglasses outside and keep rooms dim.
- Caffeine helps alertness, but stop about 6 hours before bed so it does not wreck the sleep you need to adjust.
- Keep naps short. A 20 to 30 minute nap can rescue an afternoon; long naps make it harder to sleep at night.
- Eat on local time once you have decided to adapt, and keep dinner a few hours before your planned bedtime. On short trips, stay close to your home meal times where you can.
- Move your body. In a lab study, exercise in the morning or early afternoon (body-clock time) shifted the clock earlier and evening exercise shifted it later. The effect is smaller than light, but a 20-minute hotel-room workout at the right time also helps you feel more awake. Try the workout timer for a 20-minute hotel-room session.
- Plan your most important meetings for when your body clock is in its daytime. On short trips, that usually means your home daytime.
Want better sleep at home as well? Read how to sleep better after 35, work out your bedtime with the sleep calculator, and set a fluid target for the trip with the hydration calculator.
Sources
- CDC Yellow Book 2026: Jet Lag Disorder (Riedy and Williams). Adjustment rates, pre-flight shifting, short trips, caffeine, naps, alcohol and melatonin
- Eastman and Burgess (2009), How to travel the world without jet lag, Sleep Medicine Clinics
- American Academy of Sleep Medicine: practice parameters for circadian rhythm sleep disorders, including jet lag (published in SLEEP, 2007)
- Youngstedt, Elliott and Kripke (2019), Human circadian phase-response curves for exercise, Journal of Physiology
This jet lag planner gives general education, not medical advice. Times are estimates; body clocks vary from person to person. If you have a sleep disorder, a heart condition or diabetes, or you take medicines on a fixed schedule (such as insulin), ask your doctor how to time them across time zones before you travel.
More free tools: Sleep calculator · Workout timer · Hydration calculator · All tools