The difference between diced and chopped primarily lies in the size and uniformity of the cuts.

Diced: This technique involves cutting food into small, uniform cubes. The pieces are usually consistent in size, typically ranging from small (about 1/4 inch) to large (about 1/2 inch). Dicing is often used when precise pieces are needed for recipes, like in salsas or salads.
Chopped: Chopping is less precise. It involves cutting food into rough, irregular pieces. The size of the pieces can vary, and the cut doesn’t have to be as uniform as dicing. Chopping is often quicker and used for dishes where the shape of the pieces doesn’t matter as much, like soups or stews.
In short, dicing is about precision and uniformity, while chopping is more about speed and less concern for perfect sizes.