When did they stop making copper pennies?

Pennies in the United States were made of pure copper from 1793 to 1837, and then contained varying amounts of copper throughout the years before converting to a majority 97.5 percent zinc in 1982. At that point, the penny continued to be made with a small 2.5 percent copper.

The most common materials replacing or mixing with copper over the decades were bronze, tin, nickel, zinc and zinc-coated steel. In 1943, copper was removed from the penny in order to utilize the metal in the war effort of World War II. A small number of copper pennies were minted that year and have since become valuable collectors items.