whereBetween dates trouble for getting results in Eloquent Laravel

I have some trouble with getting the correct output of a Eloquent Query.

$checkIn  = date(request()->checkin);
$checkOut = date(request()->checkout);

$bookedRooms = App\Booking::whereBetween('checkin', [$checkin, $checkout])->whereBetween('checkout', [$checkin, $checkout])->pluck('room_id');
$availabileRooms = App\Room::whereNotIn('id', $bookedRooms->toArray())->sum('number_of_rooms');

What I have is a checkin and checkout date.

It is a database for a Hotel. The Hotel has Rooms. There a different types of Rooms, and each Room can exist multiple times. That is set in the Room-table with an integer value of the rooms available in column number_of_rooms

What I want, it the output of the percentage that is still available of a specific Room and the total availability of Rooms in the date range.

I thought that it can be achieved with the code given before, but that can be not.

Can someone help me out? Probably it's simpler then I can think of now..

via Chebli Mohamed