The "theoretical" weight of a pre-1982 cent is 3.1 grams. The "theoretical" weight of a post-1982 cent is 2.5 grams.   From 1962 to 1982, cents were a brass alloy, consisting of 95% Cu and 5% Zn. From 1982 to 2008, cents were copper plated zinc, consisting of 97.5% Zn and 2.5% Cu.   As of September 6, 2011: The metal in a pre-1982 penny was worth $0.026.   The metal in a post-1982 penny was worth $0.0058.   In an effort to reduce costs, one million aluminum pennies were mented in 1974. Because of strong objections from the medical profession, those pennies were never put into circulation. Why would the medical profession be against aluminum pennies? Think about it. Your facilitator will ask!   More about U. S. Coins from Wikipedia.