Hash # vs Musical Sharp ♯: What’s the Difference?

The number sign # and the musical sharp sign ♯ can look surprisingly similar, especially at small sizes or in fonts with narrow strokes.

They are different Unicode characters with different purposes.

# is U+0023 NUMBER SIGN. It is also widely called the hash sign or simply hash, and it has several other traditional names and uses.

♯ is U+266F MUSIC SHARP SIGN. It is the dedicated Unicode character for the familiar sharp accidental in musical notation.

Hash and Musical Sharp at a Glance

The two characters are part of a wider family of punctuation and symbol characters where a similar shape can represent a completely different idea.

What Is the # Symbol?

# is U+0023 NUMBER SIGN.

It is part of ASCII and appears directly on many computer keyboards. Because it has been reused in many contexts, it does not have one universal meaning.

You may encounter it as:

• a number sign;
• a hash sign;
• the marker at the start of a hashtag;
• a pound sign in some North American usage;
• a programming or scripting character;
• a marker in headings, comments, commands, or identifiers.

Unicode records several familiar names for U+0023, including hashtag, hash, crosshatch, and octothorpe.

Why Is # Called the Number Sign?

NUMBER SIGN is the formal Unicode name.

One traditional use associates the symbol with a numbered item:

#5

Depending on the convention, this may be read as “number five.” The position and exact interpretation can vary by region and context.

Why Is # Called a Hash?

Hash is a widely used name for U+0023, particularly in computing.

The character appears in many technical systems, including programming languages, shells, configuration files, markup, and web-related syntax.

Its exact function depends on the system. A hash may begin a comment in one language, have another syntactic role in a second language, and have no special meaning in a third.

What Is a Hashtag?

A hashtag commonly consists of U+0023 followed by a word or phrase written according to the rules of the platform:

#Unicode

#Typography

The word hashtag usually refers to the tagged expression as a whole. Unicode does not encode a separate hashtag character; the mark at the beginning is still U+0023 NUMBER SIGN.

Why Is # Sometimes Called the Pound Sign?

In North American English, # has also traditionally been called the pound sign, and the corresponding telephone key is often called the pound key.

This should not be confused with the British pound currency symbol:

£ — U+00A3 POUND SIGN

The everyday name pound sign can therefore refer to different symbols depending on context, while their Unicode identities remain distinct.

What Is the Musical Sharp Sign ♯?

♯ is U+266F MUSIC SHARP SIGN.

It is a musical accidental used to alter the written pitch of a note. In conventional Western chromatic notation, a sharp normally raises the written note by one chromatic semitone. Specialized notation systems can use additional accidental conventions.

For example:

F♯

is read as F-sharp.

# vs ♯

Compare:

# — U+0023 NUMBER SIGN

♯ — U+266F MUSIC SHARP SIGN

They are not two font styles for the same character.

Unicode specifically notes that U+266F ♯ is preferred when a musical sharp is intended.

Why Do # and ♯ Look Similar?

Both characters are built from intersecting strokes, so they have a similar overall silhouette.

In many typefaces, the number sign uses two roughly horizontal strokes crossing two more vertical or slanted strokes. A musical sharp is usually drawn with proportions suited to music notation.

Font design varies, however. In some fonts the distinction is obvious; in others it is subtle. Shape alone is not a reliable way to identify the character.

Can # Be Used Instead of ♯?

In informal plain text, people often type # because it is readily available on the keyboard.

For example:

F#

may be understood as F-sharp when the musical context is obvious.

The dedicated Unicode form is:

F♯

The two expressions may communicate the same intended note to a reader, but they contain different characters.

Why F# Does Not Necessarily Contain a Musical Sharp

Context matters even more when the same shape appears in a proper name.

The programming language F# is written in ordinary text with the ASCII number sign:

F#

It should not be silently changed to:

F♯

The second form replaces U+0023 with the Unicode music sharp sign and therefore creates a different text string.

What About C#?

The programming-language name C# is likewise written with the number sign in ordinary technical text:

C#

Replacing it with:

C♯

changes the encoded character even though the musical association remains visually obvious.

Why the Difference Matters in Search

Exact string matching sees:

F#

and:

F♯

as different text unless the search system deliberately treats the characters as related.

The distinction can affect:

• search results;
• programming-language names;
• music databases;
• filenames;
• tags;
• text comparison.

Sharp ♯ vs Flat ♭ and Natural ♮

The sharp sign belongs to a familiar group of musical accidentals:

These are dedicated music symbols rather than ordinary keyboard punctuation.

# vs Numero Sign №

Because U+0023 can function as a number sign, it is also useful to distinguish it from:

№ — U+2116 NUMERO SIGN

Both can appear with numbers, but they belong to different typographic traditions and have different Unicode code points.

For example:

#12

and:

№ 12

are not the same Unicode text.

Why the Difference Matters in Code

Programming languages and technical formats generally require the exact characters defined by their syntax.

If a language expects U+0023 #, replacing it with U+266F ♯ changes the input. A compiler, interpreter, parser, or other software tool does not have to treat the music symbol as equivalent.

How to Tell Whether You Have # or ♯

Context is the strongest first clue:

• A mark starting a hashtag is #.
• A character used by programming syntax is likely # when the language defines U+0023.
• An accidental modifying a musical note may be ♯.
• The programming-language names C# and F# use # in ordinary technical text.

Visual appearance alone is not enough because fonts can make the characters unusually similar.

If a copied symbol is unclear, paste it into What Is This Symbol and inspect its exact Unicode identity.

The Main Difference

• # is U+0023 NUMBER SIGN, widely called the number sign or hash;
• ♯ is U+266F MUSIC SHARP SIGN;
• Unicode prefers ♯ when an actual musical sharp is intended;
• technical names such as C# and F# use # in ordinary text;
• the characters may look similar but are not interchangeable in exact digital text.

The surrounding context tells you what the mark probably means. The code point tells you which character is actually present.