How Long Does Jet Lag Last? — Jet Lag Recovery Calculator
Wondering how long jet lag lasts after a long flight? This jet lag recovery calculator estimates your recovery time in days, rates how severe your trip is likely to feel, and builds a simple sleep-shift plan based on the time zones you cross and your direction of travel. It's a quick, free estimate based on a common rule of thumb — not medical advice.
Enter your trip details
Your results
How to use this calculator
Enter the number of time zones you will cross (1 to 12), pick whether you're flying east or west, and add your arrival date. Everything recalculates instantly as you type, so you can try different trips and see the recovery estimate change.
Optional: if you plan to start shifting your bedtime before the trip, enter how many days of pre-trip shifting you'll do. Each day of shifting moves about one hour of the adjustment before the flight, which shortens your post-arrival recovery by roughly the same amount.
Your results show the estimated recovery days, the date you're likely to feel back to normal, a severity band (mild, moderate, or severe), and a simple day-by-day bedtime-shift schedule you can follow before and after the flight.
How it works
This calculator uses a commonly cited rule of thumb, clearly labeled as a rough estimate: flying east takes about 1 recovery day per time zone crossed, while flying west takes about two-thirds of a day per zone (rounded to the nearest half day). Eastward travel is harder because it shortens your day — your body clock resists falling asleep earlier — while westward travel lengthens it, which the body accepts more easily.
The schedule assumes you can shift your sleep by roughly one hour per day toward destination time. Pre-trip shift days are subtracted from the total, so shifting your bedtime a few days before departure genuinely shortens the recovery shown after arrival.
Individual variation is large: age, sleep habits, flight timing, cabin rest, light exposure, and caffeine all move the real number up or down. Treat the result as a planning estimate, not a medical prediction.
Practical jet lag tips
Use light on purpose. After flying east, get bright morning light at your destination to pull your clock earlier; after flying west, evening light helps push it later. Avoid bright light at the wrong end of the day.
Shift sleep before you fly. Move bedtime about one hour per day toward destination time for several days before departure — earlier for eastbound trips, later for westbound ones. Even two or three days makes a noticeable difference.
Keep naps short and stay hydrated. Limit daytime naps to 20–30 minutes, drink water during the flight, and time caffeine so it doesn't push your bedtime later than you want. This is general wellness information, not medical advice — if you have sleep concerns, talk to a clinician.
Frequently asked questions
How long does jet lag last?
As a rule of thumb, allow about one recovery day per time zone crossed when flying east, and about two-thirds of a day per zone when flying west. A 6-hour time difference eastbound usually takes around 6 days to adjust to, while the same trip westbound takes about 4 days. Individual recovery varies a lot, so treat this as a rough estimate.
Is jet lag worse when flying east or west?
Flying east is generally harder. Traveling east shortens your day, and most body clocks resist falling asleep earlier. Westward travel lengthens the day, which the body adapts to more easily — roughly two-thirds of a day of recovery per time zone, versus a full day per zone eastward.
How can I use this jet lag calculator to plan my trip?
Enter the time zones you will cross, your direction, and your arrival date. The calculator shows your estimated recovery days, the date you will likely feel back to normal, a severity rating, and a bedtime-shift schedule. If you will shift your sleep before the trip, add those days to see your post-arrival recovery shrink.
Can I prevent jet lag before I fly?
You can reduce it. Shift your bedtime about one hour per day toward your destination's time for several days before departure — earlier for eastward flights, later for westward ones. Morning sunlight at your destination also helps after eastward travel, as does staying hydrated and keeping naps short.
Is this calculator medical advice?
No. This tool gives a rough, general estimate based on a commonly cited rule of thumb. It is not medical advice, and it does not account for personal health, sleep disorders, or medication. If you have concerns about sleep or travel health, talk to a clinician.