That appears to be a 3 gallon pot to me but im not really sure. That is also assuming its full of growing media. I really don't use much perlite unless using coco coir based mixes.
1 quart of perlite though seems like very little for a 3 gallon pot without any perlite already added. My best guess is around 4 quarts total.
it has some perlite from the potting mix but it's very little.