Despite the fact that there are no specific rules, you can make a clear estimate about the number of boxes you may need for moving simply by looking at your home and its objects.
Perhaps one of the easiest and most common methods of calculating how many boxes you may need is by looking at the square footage of your house. Quite obviously, the larger the home, the more the items in it, and therefore the higher the number of moving boxes that you may need.
For 400-700 square feet, you may need up to 7-15 small boxes, 9-15 medium sized boxes, 6 large boxes and about 3 extra-large boxes. For a bigger space, namely that of 700-1200 square feet, you may need up to 22 small boxes, 15-22 medium boxes, 7-10 large boxes and about 4-6 extra-large boxes.
For spaces of 1200-1700 square feet, you may need 31-36 small boxes, 24-35 medium boxes, 15-20 large boxes and around 10-12 extra large boxes.
For even bigger spaces, of over 2000 feet, you may need up to 42 small boxes, 35-47 medium boxes, 21-25 large boxes and about 12-15 extra large boxes.
The general consensus is that for each room you will need around 10 small boxes, 8 medium boxes and 5 large moving boxes. Find boxes through local moving companies like Your Personal Mover, or at big box home improvement stores.