How many pounds of chuck roast for 20 people?

For a gathering of 20 people, you typically need about 1/2 to 3/4 pound of chuck roast per person, depending on whether it's the main dish and if there are other sides served. This means you would need approximately 10 to 15 pounds of chuck roast to adequately serve 20 people. Adjust the amount based on your guests' appetites and any additional dishes.