Depending on the type of tomato, the number per pound varies. For medium globe tomatoes, there are approximately three tomatoes per pound. For smaller plum tomatoes, there can be as many as eight per pound. For cherry tomatoes, the smallest type, there are typically 25 to 30 per pound.
When tomatoes are diced, 2 cups are generally equivalent to 1 pound of tomatoes. In terms of serving size, a half pound, or about one large tomato, is considered one serving of tomato. These are estimates that can be used in cooking; however, for the most accuracy, use an inexpensive kitchen scale to measure produce.