It's about nine-tenths as big as a Hot Tub.
In other words, 648.20 quarts is 0.8530 times the size of a Hot Tub, and the size of a Hot Tub is 1.170 times that amount.(for Lifesmart Rock Solid Simplicity Plug and Play 4 Person Spa With 12 Jets) (a.k.a. Spa, a.k.a. Jacuzzi, a.k.a. Whirlpool) (Advertised Capacity)
An average, four-person hot tub holds 760 quarts of water. Modern hot tubs became popular outside of Japan starting in about 1940.
It's about four times as big as a Bathtub.
In other words, 648.20 quarts is 3.80 times the size of a Bathtub, and the size of a Bathtub is 0.260 times that amount.(a.k.a. bath, a.k.a. tub) (for Bootz Industries Aloha 5 ft. Left Hand Drain Soaking Tub)
The capacity of a typical bathtub is 170 quarts. Historically, bathtubs have been made of various materials including marble, terracotta, silver, gold, and iron but the size and shape of the tubs has changed little in their 7,000 year history.
It's about eight times as big as a Car Gas Tank.
In other words, 648.20 quarts is 8.10 times the size of a Car Gas Tank, and the size of a Car Gas Tank is 0.1230 times that amount.(for 2009 Ford Taurus)
A car gas tank (for example, that of a 2009 Ford Taurus) holds 80 quarts of gas. In contrast, the Curved Dash Oldsmobile — the first mass-produced car — had a fuel capacity of just 21.10 quarts.
It's about ten-and-a-half times as big as a Beer Keg.
It's about one-twentieth as big as a Concrete Mixer Truck.
In other words, the size of a Concrete Mixer Truck is 18 times 648.20 quarts.(a.k.a. cement mixer, a.k.a. cement mixer truck, a.k.a. cement transport truck, a.k.a. concrete mixer, a.k.a. concrete transport truck, a.k.a. in-transit mixer)(standard size; drum capacity)
A concrete mixer truck has a drum volume of up to 12,000 quarts. Concrete mixer trucks can be in transit for about 90 minutes before the concrete dries — if the concrete dries while in the drum, jackhammers or even dynamite must be used to remove it.
It's about 55 times as big as a Basketball (packed).
In other words, 648.20 quarts is 55.2619158340 times the size of a Basketball (packed), and the size of a Basketball (packed) is 0.018095644802 times that amount.(64% packing density) (NBA official ball standards, Size 7)
A NBA official ball, manufactured by Spalding, is a Size 7 ball measures about 7.50694205450 quarts. These balls have 4,118 pebbles each with a diameter of 2.5 mm
It's about 75 times as big as a Bowling Ball (packed).
In other words, 648.20 quarts is 74.5050292910 times the size of a Bowling Ball (packed), and the size of a Bowling Ball (packed) is 0.013421912715 times that amount.(64% packing density) (USBC specifications; tenpin)
According to United States Bowling Congress specifications, a tenpin bowling ball should measure at least 10.795 cm (4.25 in) in radius for a total volume of about 5.56805364610 quarts. Because regulation balls measure the same diameter irrespective of their weight, ball density varies by size and balls weighing less than about 5 kg (11 lbs) will float in water.