Hash Symbol # Copy & Paste: Hashtag, Number Sign & Uses

The hash symbol (#) goes by many names — number sign, pound sign, hashtag, octothorpe, and sharp. It has evolved from a simple shorthand for "number" into one of the most powerful symbols in social media and programming. Every hash variant is below, ready to copy.

All Hash and Sharp Symbols

What Is the Hash Symbol Called?

The # symbol has more names than almost any other character, and the name you use probably depends on where you live and what you do:

• Hash / Hash symbol: Used in the UK, Australia, New Zealand, and most English-speaking countries outside North America
• Pound sign: Used in the United States (not to be confused with the British pound currency symbol £)
• Number sign: Formal name in North America, used when # means "number"
• Hashtag: Used on social media when # prefixes a topic tag
• Octothorpe: Formal/uncommon name, allegedly coined by Bell Labs engineers in the 1960s
• Sharp: In music notation, the similar-looking symbol indicates a note should be raised by a semitone
• Grid / Crosshatch: In some European languages and contexts

The Rise of the Hashtag

The hashtag transformed the # symbol from a utilitarian punctuation mark into a cultural phenomenon. Chris Messina proposed using # to tag topics on Twitter in 2007, and by 2009 Twitter officially adopted hashtags as clickable links. Instagram, Facebook, TikTok, LinkedIn, and virtually every social platform followed.

Today, hashtags organize content, start movements, build communities, and drive marketing campaigns. #BlackLivesMatter, #MeToo, and #ClimateStrike became global movements through the humble hash symbol.

How Hashtags Work

• Prefix any word or phrase with # to make it a hashtag
• Hashtags cannot contain spaces (use CamelCase for readability: #SocialMedia not #socialmedia)
• Clicking a hashtag shows all other posts using the same tag
• Popular hashtags can trend regionally or globally

Uses of the Hash Symbol

Programming

• Comments: In Python, Ruby, Bash, and many others, # starts a comment line
• Hex color codes: In CSS and HTML, # precedes color values like #FF5733
• URL fragments: In web URLs, # links to a specific section of a page
• C preprocessor: In C and C++, #include and #define are preprocessor directives
• Markdown headings: In Markdown, # creates headings (## for h2, ### for h3)
• Shell scripting: #! (shebang) at the start of scripts specifies the interpreter

Everyday Use

• Number: #5 means "number five" (common in addresses and lists)
• Phone menus: "Press 1 for sales, press # to return to the main menu"
• Social media: #topic tags for content discovery
• Medical charts: # is sometimes used as shorthand for "fracture"

How to Type the Hash Symbol

Windows

• US keyboard: Shift + 3 produces #
• UK keyboard: The key to the right of Shift (no shift needed)

Mac

• US keyboard: Shift + 3 produces #
• UK keyboard: Option + 3 (or the dedicated # key)

Mobile

On iOS and Android keyboards, tap the number key (123 or ?123) to find the # symbol. On some keyboards it shares a key with the pound currency symbol.

HTML Entities

Quick Copy Section

All hash-related symbols in one place:

# ♯ ＃ №

Highlight, copy, paste. From number sign to hashtag, it all starts here.