What is the biggest size of a hot air balloon?

The largest hot air balloon ever constructed is the "Big Balloon," which measures approximately 120 feet (36.6 meters) in height and 100 feet (30.5 meters) in diameter when fully inflated. This massive balloon has a volume of about 6,000,000 cubic feet (about 170,000 cubic meters). Hot air balloons can vary widely in size, but many are typically much smaller, designed to carry a limited number of passengers.