When you're serving a large group of people with soup you should plan on at least 1 gallon of soup for every 8 people.
So if you have 8 people to serve with soup then you should have 1 gallon of soup.
If you're serving 16 people then you should have 2 gallons of soup.
One gallon of soup can sometimes feed 12 people depending on how much they eat but you should have at least 1 gallon of soup for every 8 people.
Having more soup than you need is better than not having enough.
You can save any leftovers and bring them home or freeze the leftover soup for later.
For child-sized entrées of soup one gallon is needed for every 16 children.
When serving soup as a side, one gallon is needed for every sixteen adults and thirty-two children.
The average soup serving as a side dish is between 3/4 and 1 cup.
When the soup is served as the main course, plan on about 1 1/2 cups per person.
Use your oven to keep food warm or your stove to keep your soups warm.
Other items like the thermos, toaster oven, and crock-pot are also effective at keeping food warm for your dinner guests.