JetReset

Jet Lag Recovery Calculator

Timezones crossed and direction of travel — a rough estimate of how many days to feel normal again.

Timezones crossed

Estimated recovery

12 days

Eastbound jet lag recovers slower

What you entered

Timezones crossed: 8Direction: Eastbound

1
Timezones crossed
|8|= 8
2
Apply eastbound factor
8 × 1.5= 12.0 days

Result

Recovery time: 12 days

Crossing 8 timezones eastbound, expect roughly 12 days to fully adjust.

Estimated jet lag recovery by time zones crossed

The common rule of thumb is about one day of recovery per time zone crossed, and roughly half again as long travelling east.

Time zones	Flying west	Flying east	A route with this gap
1	1.0 days	1.5 days	London and Paris
3	3.0 days	4.5 days	New York and Los Angeles
5	5.0 days	7.5 days	New York and London
6	6.0 days	9.0 days	Paris and New York
8	8.0 days	12.0 days	London and Los Angeles
9	9.0 days	13.5 days	London and Tokyo
12	12.0 days	18.0 days	London and Auckland

Eastward travel is harder because it asks your body clock to run early, and the human circadian rhythm naturally drifts slightly longer than 24 hours, so delaying is easier than advancing. Real recovery plateaus rather than scaling linearly, so treat the longest rows as an upper bound. Morning light after an eastward flight and evening light after a westward one both help shift the clock in the right direction.

Why eastward is harder

Flying east shortens your day, which is harder for your body clock to adjust to than the lengthened day you get flying west — most people recover roughly 50% slower eastbound.

Frequently asked questions

I'm flying from LA to Tokyo (crossing 8 time zones east) — how long to recover?

Roughly 8-12 days for full adjustment, at about 1-1.5 days per timezone crossed eastbound. You'll feel significantly better after 3-4 days, but fine-tuning your sleep schedule takes longer.

Why is jet lag worse flying east than west?

Flying east shortens your day, forcing your body clock to advance — which is harder than the delay caused by flying west. Most people adapt about 50% slower going east, which is why a 6-timezone eastbound trip can feel worse than a 6-timezone westbound one.

Does jet lag affect north-south travel?

No. Jet lag is caused by crossing time zones, not distance traveled. A flight from New York to Buenos Aires covers 5,000+ miles but only crosses 1-2 time zones, producing little or no jet lag.