Dollar Sign ($)

$ is the one major currency symbol that's already sitting on every standard keyboard — Shift+4 on a US layout, no Alt code or Option key required. That's also what makes it an outlier on this site: every other currency spoke here (€, £, ¥, ₹, ¢) exists partly to explain how to type a character your keyboard doesn't have. Dollar's story is different — and arguably stranger. Despite being typed billions of times a day, exactly how the glyph itself came to look the way it does is still, per Britannica, "a matter of debate."

Start with the myth you've probably heard: that $ is a "U" laid over an "S," short for "United States." It's a good story — Ayn Rand even wrote it into Atlas Shrugged in 1957 — but it isn't history. Mathematical historian Florian Cajori dismantled it in 1929 in A History of Mathematical Notations, after combing through 18th-century manuscripts and finding the $ symbol already in regular use years before the United States existed. A country can't be the source of a symbol that predates it.

The leading alternative, and the one endorsed by the U.S. Bureau of Engraving and Printing, traces $ to "Ps" — the handwritten abbreviation traders used for the Spanish peso (the "piece of eight" that dominated 18th-century American and Caribbean commerce). Clerks wrote a capital P with a small S floating above it; write that quickly enough, over and over, and the loop of the P collapses down onto the S, leaving one or two vertical strokes struck through the letter. The earliest confirmed manuscript use dates to the 1770s, in the ledgers of English-American merchants trading with Spanish America. One especially clean specimen: a New York diarist's 1776 journal, examined by Cajori, spells out "dollar" in full every day from June 10 through August 20 — then switches to the $ symbol on August 21, 1776, and never looks back.

A second, weaker theory ties $ to the two Pillars of Hercules stamped on Spanish "pillar dollar" coins, each pillar wrapped in an S-shaped banner reading Plus Ultra. It's a real, historian-acknowledged theory — but Britannica is blunt that "there is little evidence" it's actually where the symbol came from, beyond a passing visual resemblance. Treat it as a plausible influence on the coin imagery of the era, not a rival explanation to the Ps theory.

The written symbol reached print surprisingly late relative to its manuscript use: the earliest known printed dollar sign dates to 1797, cast in type by Philadelphia typefounder Archibald Binny, and the character didn't become common in print until after 1800.

Look closely at old currency documents and you'll find two forms: a single vertical stroke through the S, and a double stroke. Both are original — that same 1776 diary Cajori examined shows 11 single-stroke dollar signs alongside 3 double-stroke ones, written by the same hand in the same year. The double-stroke form eventually acquired its own name and second life: it's called the cifrão in Portuguese, and was used as a thousands separator in the Brazilian real and a decimal separator in the Portuguese escudo (until the euro replaced it in 2002); it still marks the Cape Verdean escudo today.

Here's the part worth getting right if you're typing either one: Unicode does not give the cifrão its own code point. Both the one- and two-stroke forms share U+0024 — which one renders is purely a matter of the font you're using, not a different character you can select. A 2019 proposal to encode a distinct "escudo sign" was submitted to the Unicode Technical Committee and was not adopted, so as of the current standard, this stays a typeface choice, not a separate symbol.

Unlike every other currency symbol on this site, $ needs no special input method on a US keyboard — it's plain ASCII, sitting on the Shift+4 key. The methods below matter for non-US layouts, markup languages, and — in one specific case — a language where your keyboard's dollar key actively gets in the way.

$ is one of the most overloaded characters in computing, entirely because it's plain ASCII: PHP and Bash both use it to prefix every variable ($name, $HOME), regular expressions use it as the end-of-line anchor, and jQuery famously claimed $ as its global function alias. None of that is currency — it's just a distinctive, easy-to-type symbol that language designers kept reaching for.

The same instinct shows up in branding: stylizing a name with $ in place of S is a deliberate, recognizable move — Ke$ha, A$AP Rocky, and Ty Dolla $ign all adopted it as a stage-name signature, using the currency association on purpose rather than by accident.