Do I follow the 'until' stamped date on my B-2 visa or the 180-day rule?

I entered the U.S on April 9, and they stamped my passport and visa with the admission stamp that says 'until - OCT 8', but that is 183 days and I thought the limit was 180 days.
Does that mean I can leave on October 8th if my stamped tourist visa says admitted until October 8th? Or do I have to before the 8th - and leave by October 7th? Or should I calculate 180 days from April 9 myself and leave then?
Best Answer
There is no "180 day rule". The regulations allow B-2 to be admitted for up to 1 year, but they are usually admitted for 6 months. 6 months is not a particular number of days (months have various lengths), and it matches what you were admitted for -- the period of time from April 9 to October 8, including both the days April 9 and October 8 themselves, is exactly 6 months. In any case, the officer has discretion to admit for a different length of time, so you can't argue with it if they count the months differently anyway.
And yes, if you are admitted until October 8, that is until the end of the day on October 8.
Always check your electronic I-94 to make sure they didn't write down the wrong date.
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