When traveling from west to east then yes, you lose a day. But,
when travelling from east to west you gain a day.
Example: American Samoa is east of the dateline and independent Samoa is west of the dateline, although there is only about 60 nautical miles between the islands. So Wednesday in American Samoa is Thursday in independent Samoa.
It becomes one day earlier.
The International Date Line separates Day 1 from Day 2 across the globe. Thus, if you are crossing the Internationa Date Line, you may be a day ahead or behind of the place you have travelled from.
You lose a day
if you travel east across the international dateline your calendar would be moved back a day.If you traveled west, you would move your calendar a day ahead.Weird, huh?
yup
You go forward one day
Yes. If you travel from west to east across the International Date Line, the date will change to one day earlier.
the international date line
If you are crossing date line from west to east you'll gain one day.
Across the united states
180°
You don't gain a day by traveling West, only by traveling East. You lose a day going West.