Jet lag usually lasts a few days, though how long it lasts depends on how far you traveled, your personal rhythms, and your overall health. Many people feel better within a few days after arriving; for some, it can take up to about a week to feel fully adjusted. A common rule of thumb is roughly one day of recovery per time zone crossed, and eastward trips often feel harder than westward ones.
Source: Cleveland Clinic — Jet Lag.