Turn a long-haul trip into a practical sleep and light plan—before takeoff and after you land.
Tell us about your trip
Enter the cities you’re flying between. We’ll handle the clock change for your departure date.
Your day-by-day plan
General information only — not medical advice. Talk to your doctor before using melatonin or any sleep aid, especially if you take other medications or have a health condition.
Jet lag, answered
Is jet lag worse flying east or west?
Eastward travel is usually harder because the body has more difficulty advancing its internal clock. The CDC gives average adaptation rates of about 1 hour per day eastward and 1.5 hours per day westward.
How does light exposure help jet lag?
Timed light exposure is the main treatment described by Harvard Health. Morning light generally shifts your clock earlier, while afternoon or evening light shifts it later—so timing matters.
Should I take melatonin for jet lag?
Harvard Health describes 1–3 mg before bed on the day of travel and for up to four days after arrival. Melatonin is not regulated by the FDA, so the amount in a supplement may vary from what is printed on the label. Long-term safety information is limited, so talk with your doctor before using it.
Should I try to sleep on the plane?
Try to align sleep with nighttime at your destination. The CDC recommends minimizing alcohol and caffeine to support in-flight sleep; after arrival, short 20–30 minute naps can support alertness without disrupting the next night’s sleep.
Does caffeine help with jet lag?
Caffeine can support alertness during the local day. The CDC advises stopping it about six hours before bedtime so it does not interfere with sleep.
How long does jet lag last?
It depends on which way you fly. Per the CDC, your body clock adjusts about 1.5 hours per day after westward travel and about 1 hour per day after eastward travel — so a 6-hour time difference takes roughly 4 days heading west and 6 days heading east. Shifting your sleep before the trip and timing light exposure can shorten that.
Turn a long-haul flight into a plan, not a lost week
Long flights don’t have to mean lost days. The Jasmine Alley Jet Lag Calculator builds you a personalized, day-by-day plan to reset your body clock — before you take off and after you land.
Enter the cities you’re flying between. No timezone math required: the calculator works out the clock change for your exact travel dates, including daylight saving. Add your flight times and your usual bedtime and wake time, tell it whether you’re a morning or night person and how long your trip is, and it generates your plan:
- Three pre-trip days that gradually shift your sleep toward destination time
- Travel-day guidance, including when to try to sleep on the plane
- Up to five arrival days with timed light exposure, sleep targets, naps, caffeine timing, and melatonin guidance
The whole plan is free — no account, no email required. Download it as a text file or print it and take it with you.
How the plan works (in plain language)
Your body runs on an internal 24-hour clock, and flying across time zones leaves that clock set to home time while you’re living on destination time. That mismatch is jet lag — and it fades as your clock catches up, which happens at a predictable pace. Per the CDC, the average traveler adjusts about 1.5 hours per day after flying west and about 1 hour per day after flying east. So a six-hour time difference takes roughly four days heading west and six days heading east. Shifting your sleep an hour a day toward destination time for a few days before you fly can shorten that adjustment, which is why your plan starts three days before departure.
Light is the strongest signal for resetting that clock, and timed light exposure is the main treatment described by Harvard Health. Morning light tends to shift your clock earlier, while afternoon or evening light shifts it later — so getting daylight (or avoiding it) at the right local times is the core of every arrival day in your plan. The calculator estimates your body clock’s nightly low point from your usual bedtime and wake time, then times the light guidance around it, nudged toward your natural morning or evening tendency.
On trips shorter than two days, the plan keeps you on home time instead of adapting — for a quick turnaround, fully resetting your clock isn’t worth it. And if you’re crossing fewer than three time zones, most travelers adjust quickly with just the basics: daylight, sensible caffeine, and one good night’s sleep.
Why is jet lag worse flying east?
Flying east is usually the harder direction because your internal clock has more difficulty advancing (shifting earlier) than delaying (shifting later). The numbers tell the story: the CDC gives average adaptation rates of about 1 hour per day eastward versus about 1.5 hours per day westward. That’s why an eastbound red-eye can leave you foggy for most of a week while the westbound return feels easier — and why the eastbound plans lean harder on pre-trip sleep shifting and carefully timed morning light.
Sleep, caffeine, and melatonin on the road
On the plane, try to sleep during nighttime at your destination — your plan shows you exactly when that is. The CDC recommends minimizing alcohol and caffeine to support in-flight sleep. Once you’ve landed, caffeine can help you stay alert during the local day, but the CDC advises stopping it about six hours before bedtime so it doesn’t interfere with sleep. Short 20–30 minute naps after arrival can support alertness without disrupting the next night’s sleep.
Your plan also includes melatonin guidance: Harvard Health describes 1–3 mg before bed on the day of travel and for up to four days after arrival. Note that melatonin is not regulated by the FDA, so the amount in a supplement may vary from what is printed on the label, and long-term safety information is limited — talk with your doctor before using it, especially if you take other medications or have a health condition.
General information only — not medical advice. Last reviewed September 22, 2026.
