Why is the dime smaller than the nickel?

The first U.S. 5-cent coins, starting in the 1790s, were made of a silver and copper alloy and were smaller than a dime. Called half-dimes, they contained one-twentieth of the amount of silver found in the silver dollar.

The half-dime, at exactly half the size of a dime, proved to be too small for convenient handling, according to the U.S. Mint. Also, silver coins of all denominations were hoarded during the Civil War, according to Littleton Coin Co. The nickel was introduced in 1866 to replace the half-dime. A larger coin, the nickel is minted from an alloy of 25 percent nickel and 75 percent copper.