Jet lag ruins more trips than bad weather. You land excited, but your body is still on home time, so you feel sleepy at lunch and wide awake at three in the morning. The Light Exposure Jet Lag Planner was built to fix that gap before it starts. It turns your sleep times, flight details, and time zones into a clear plan you can follow from day one. You do not need an account, and you do not need to install anything. Open the tool, enter a few details, and get a clear result in seconds. That simple step, done at home, saves days of tiredness abroad.
This tool works in your browser. Enter whether you fly east or west, how many time zones you cross, your wake time, and your bedtime. The planner gives you a bright-light window and a dark window, so daylight itself resets your body clock. The result appears below the form, in plain lines you can read at a glance. You can change any value and run it again, so the plan improves as your trip details become clearer. Save the result, or copy it into your notes, and take it with you. The tool never asks for personal details, and nothing you type leaves your device, because all the maths runs on the page itself.
Why does a sleep plan matter so much? Because the body clock does not jump to a new time zone in one night. It moves about one hour per day, so a six-hour change needs almost a week. Travellers who ignore that gap plan full days on empty energy, then wonder why the trip feels like a blur. When you plan sleep, light, meals, and naps around the new time, each day gets a little easier. You enjoy the places you came to see, instead of fighting your own body to stay awake.
How to use it, step by step. First, gather your times: your normal bedtime, your flight details, and the time difference to your destination. Second, enter them in the form, in the format shown in each box. Third, press the button and read the result from top to bottom. Fourth, change one thing at a time if the result looks tight, and run it again. A good plan usually needs two or three short tries, and that is normal. The goal is not a perfect plan. The goal is a plan your body can actually follow.
Start with the example already in the form. It shows a typical trip, with sensible times and a realistic shift. Run it once, just to see the shape of the result. Then replace the example with your own times and details, and run it again. Compare the two results. If your own plan asks for a huge shift in one day, that is a warning sign, not a challenge. Spread the shift over more days, or accept a lighter first day, and the whole trip will feel calmer at once.
Light is the strongest tool for resetting the body clock, and it is free. Morning light pulls the clock earlier, evening light pushes it later, and the wrong light at the wrong time can push it the wrong way. That is why direction matters: east and west need opposite light plans. Pair bright light with dark evenings, dim the lights before bed, and keep screens away late at night. Daylight then works for you, not against you.
Three tips make any result better. Get bright light at the right time of day, and keep evenings dim before bed. Eat at destination times as soon as you can, even if you are not hungry yet. Keep the first day light, so a delay or a bad night does not ruin the plan. If a result looks hard, do not force it. Move one step to another day, or shorten the shift, and try again. A gentle plan you follow beats a strict plan you abandon.
Can I use this tool for free? Yes, it is free, with no account and no sign-up. Does it work on a phone? Yes, it works in any modern browser, on a phone or a computer. Can I change the plan later? Yes, change any value and run it again as often as you like. What if my shift looks too big? Spread it over more days before the flight, or plan a lighter first day after arrival. The tool shows the maths clearly, so you can see exactly how the plan was built.
Spanish version: Planificador de Exposición a la Luz por Jet Lag