Where does the dollar sign come from?

No one knows for certain, but the most widely accepted explanation is that the dollar sign developed from handwritten abbreviations for the Spanish or Mexican peso, also called the piastre or piece of eight. Over time the S came to be written over the P, producing a close equivalent of the $ mark. The U.S. Treasury describes this as an evolution that happened independently in different places. The symbol was already in wide use before the United States adopted the dollar in 1785. [1] [2] [3]

According to [history.com](https://www.history.com/articles/where-did-the-dollar-sign-come-from), the Spanish peso was accepted as the basic unit of value in colonial America in the late 1700s. Its formal name was the peso de ocho reales, or piece of eight, and handwritten manuscripts from the time abbreviate it as PS. The S is believed to have been written on top of the P, approximating the $ shape. The same source says the symbol first appeared in print after 1800. [2]

A numismatic study summarized by [coinbooks.org](https://www.coinbooks.org/esylum_v10n08a12.html) gives a more specific account. It says British traders and merchants moving into West Florida and Louisiana after the change of ownership in 1764 converted the Spanish symbol for the peso into a ligature beginning about 1768. The same study traces the first conventional $ in type to 1799, not to a 1797 symbol of different makeup. [4]

[investopedia.com](https://www.investopedia.com/origins-of-the-dollar-symbol-and-its-global-impact-11763227) describes the same process: the P eventually shrank to a vertical line through the S. The name "dollar" itself comes from the thaler, a large silver coin used in the Holy Roman Empire in the 16th century, according to Georgetown's Stefan Eich. [5]

The best-known alternative comes from Ayn Rand's 1957 novel Atlas Shrugged, which said the sign came from a U superimposed over an S, the initials of the United States, with the bottom of the U removed. History.com notes that no documentary evidence supports this, and the sign was clearly in use before the United States was formed. [2]

Another theory points to the Pillars of Hercules, which appear on the reverse of the Spanish eight reales coin with an intertwining ribbon. The Royal Australian Mint says this design, together with the coin's nickname "Spanish dollar", is thought to have inspired the symbol. Investopedia lists the same theory alongside the Portuguese cifrão, a currency sign with two vertical lines. It adds that the cifrão appears to have worked as a decimal marker on coins rather than a currency symbol, though it may have influenced later signs. [6] [5]

Sources differ in how they frame these ideas. The Royal Australian Mint presents the coin-design theory as the origin, while the Treasury, History.com and Investopedia treat the peso abbreviation as the most widely accepted account. [6] [1] [2]

The United States adopted the dollar as its monetary unit in 1785, and the symbol was ubiquitous by the time the first U.S. paper dollar was issued, which History.com and Investopedia both give as 1875. [3] [2] [5]