A standard Solo cup most commonly holds 16 ounces of liquid. This size is widely used for beer, cocktails, and other beverages at parties and events due to its convenient capacity

. However, Solo cups come in several other sizes, including:

• 9 oz: often used for smaller servings or kids' drinks
• 12 oz: versatile for soft drinks and mixed drinks
• 18 oz: larger servings, popular for games or bigger drinks
• 20 oz and above: jumbo sizes for extra-thirsty moments

The classic 16 oz Solo cup typically measures about 4.5 inches tall, with a rim diameter of approximately 3.5 inches and a base diameter around 2.5 inches

. In summary, the most recognized and standard Solo cup size is 16 ounces, but other sizes are available depending on your needs.