I know everyone still likes to say 65000 because that is what it was for so many years, but the facts are that renovation to add new seats and accommodations for wheelchair access have reduced that count by 1500 seats.

Kind of sad that the attendance records can never be broken again, but this trend is happening all over college football. I would guess that the number of seats would decrease going forward, even if the stadium is renovated.

From the media guide:

LAVELL EDWARDS STADIUM
LaVell Edwards Stadium with its 63,470-seat capacity is home to BYU football. Originally Cougar Stadium, it
was built in 1964 and seated 30,000. It was expanded in 1982 to seat 65,000 permanent seats before official
capacity became 64,045 after refurbishing the middle of the east section. The capacity now sits at 63,470 due
to accomodations for wheelchair access. For the 2012 season the stadium featured new video walls and LED
ribbons on the north and south end zone stands. BYU’s 2012 average attendance of 61,161 ranked No. 3 in
the West behind only USC (87,945) and UCLA (68,481).

Stadium record: 222-67 (.768)
2013 stadium record: 5-1 (.833)
Under Mendenhall: 46-9 (.836)