What is the size of an average super giant star?

Supergiant stars are among the largest stars in the universe, with diameters that can range from about 1,000 to 2,000 times that of the Sun. Some of the most massive supergiants, like UY Scuti, can exceed 1,700 times the Sun's diameter. Their immense size results from their advanced stage of stellar evolution, where they have expanded significantly after exhausting their nuclear fuel.