How big is U.S. Penny? | Scale of the Universe

A U.S. penny, officially the one-cent coin, is 19.05 millimeters (0.75 inch) across. It is 1.52 millimeters thick and weighs 2.5 grams. The explorer's picture shows the front of a 2010 penny, with the portrait of Abraham Lincoln.

Size

The penny's width is set by federal law, which describes "a one-cent coin that is 0.75 inch in diameter". That is exactly 19.05 millimeters, because an inch has been defined as exactly 25.4 millimeters since 1959. The same law sets the dime at 0.705 inch, so a penny is slightly wider than a dime.

The law gives the penny a weight of 3.11 grams and an alloy of 95 percent copper and 5 percent zinc, but it allows the Secretary of the Treasury to change both. Today's penny is lighter, at 2.50 grams. It is made of zinc plated with copper, 97.5 percent zinc and 2.5 percent copper, and its edge is plain.

Size comparisons

Exactly 16 pennies laid side by side span a 12-inch (30.48-centimeter) ruler.
A penny is three-quarters as wide as a square inch. Laid on one, it covers about 44 percent of the square's area.
A standard glass marble, 5/8 inch (1.6 centimeters) across, is five-sixths as wide as a penny.
A stack of 100 pennies is about 15 centimeters (6 inches) tall.
The Mint estimates that about 300 billion pennies are in circulation. Laid side by side, they would stretch about 5.7 million kilometers (3.6 million miles), about 15 times the distance from Earth to the Moon.

Lincoln on the penny

Authorized by the Coinage Act of 1792, the penny was one of the first coins the U.S. Mint made. The first pennies were large copper coins showing a woman with flowing hair, a symbol of Liberty. Smaller cents were first made in 1857.

In 1909, the 100th anniversary of his birth, Abraham Lincoln became the first U.S. president to appear on a coin. The front still carries Victor David Brenner's portrait of him. Since 2010, the back has shown the Union Shield, which stands for Lincoln's role in keeping the United States a single, united country.

The end of penny production

On November 12, 2025, the Treasurer of the United States struck the last circulating penny at the Mint in Philadelphia. That ended a production run of 232 years. By then, making each penny cost 3.69 cents, up from 1.42 cents a decade earlier.

Pennies are still legal tender, and stores can still price goods in single cents. As of 2026, the Mint makes pennies only in limited numbers for collectors' sets.