The United States one-cent coin, commonly known as a penny, is a unit of currency equaling one one-hundredth of a United States dollar. The cent’s symbol is ¢. Its obverse has featured the profile of President Abraham Lincoln since 1909, the centennial of his birth. From 1959 (the sesquicentennial of Lincoln’s birth) to 2008, the reverse featured the Lincoln Memorial. Four different reverse designs in 2009 honored Lincoln’s 200th birthday and a new, permanent reverse – the Union Shield – was introduced in 2010. The coin is 0.75 inches (19.05 mm) in diameter and 0.0598 inches (1.52 mm) in thickness.

The U.S. Mint’s official name for a penny is “cent” and the U.S. Treasury’s official name is “one cent piece”. The colloquial term penny derives from the British coin of the same name, the pre-decimal version of which had a similar value. In American English, pennies is the plural form. (The plural forms pence and pee—standard in British English—are not used in American English.)

As of 2013, based on the US Mint Annual Report released in 2014, it costs the U.S. Mint 1.83 cents (down from 2.41 cents in 2011) to make one cent because of the cost of materials, production, and distribution. This figure includes the Mint’s fixed components for distribution and fabrication, as well as Mint overhead allocated to the penny. Fixed costs and overhead would have to be absorbed by other circulating coins without the penny. The loss in profitability due to producing the one cent coin in the United States for the year of 2013 was $55,000,000. This was a slight decrease from 2012, the year before, which had a production loss of $58,000,000.

History of composition

Years Material Mass (grams)
1793–1796 100% copper 13.48
1796–1857 100% copper 10.89
1856–1864 88% copper, 12% nickel (also known as NS-12) 4.67
1864–1942 bronze (95% copper, 5% tin and zinc) 3.11
1943 zinc-coated steel (also known as 1943 steel cent) 2.67
1944–1946 brass (95% copper, 5% zinc) 3.11
1946–1962 bronze (95% copper, 5% tin and zinc)
1962–1981 brass (95% copper, 5% zinc)
1982 varies: brass (95% copper, 5% zinc) or copper-plated zinc (97.5% zinc, 2.5% copper) 3.11 or 2.5
1983–present 97.5% zinc, 2.5% copper (core: 99.2% zinc, 0.8% copper; plating: pure copper) 2.5

In honor of the Lincoln cent’s 100th anniversary, special 2009 cents were minted for collectors in the same composition as the 1909 coins.

The isotope composition of early coins spanning the period of 1828 to 1843 cents reflects that of copper from Cornwall ores from England while coins after 1850 that from the Keweenaw Peninsula, Michigan ores, a finding consistent with historical records.

In 1943, at the peak of World War II, zinc-coated steel cents were made for a short time because of war demands for copper. A few copper cents from 1943 were produced from the 1942 planchets remaining in the bins. Similarly, some 1944 steel cents have been confirmed. From 1944 through 1946, salvaged ammunition shells made their way into the minting process, and it was not uncommon to see coins featuring streaks of brass or having a considerably darker finish than other issues.

During the early 1970s, the price of copper rose to a point where the cent contained almost one cent’s worth of copper. This led the Mint to test alternative metals, including aluminum and bronze-clad steel. Aluminum was chosen, and over 1.5 million of these pennies were struck and ready for public release before ultimately being rejected. The proposed aluminum pennies were rejected for two reasons: vending machine owners complained the coins would cause mechanical problems; and pediatricians and pediatric radiologists pointed out that the radiodensity of the metal inside the respiratory and gastrointestinal tracts was close to that of soft tissue, and the coins would therefore be difficult to detect in X-ray imaging. One aluminum cent was donated to the Smithsonian Institution.

The cent’s composition was changed in 1982 because the value of the copper in the coin started to rise above one cent. This was mainly caused by inflation. Some 1982 pennies used the 97.5% zinc composition, while others used the 95% copper composition. With the exception of 2009 bicentennial cents minted specifically for collectors, United States cents minted after 1982 have been copper-plated zinc. In Fiscal Year 2013, the average one-cent piece minted cost the U.S. Mint 1.83 cents, down from 2.41 cents apiece in FY 2011.

Distinguishing between the bronze and copper cents and the newer, zinc cents can be done by dropping the coin on a solid surface. The predominantly copper coins produce a higher-pitched ringing sound, while the zinc coins make a lower-pitched “clunk”. In addition, a full 50-cent roll of pre-1982/3 coins weighs 5.4 oz compared to a post-1982–83 roll which weighs 4.4 oz.

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