Bold Letters (Bold Text)

Bold text on a web page is normally formatting: the same letter B, drawn heavier because a style tells the browser to. The letters on this page are different. 𝐁 is not a styled B but a separate character, U+1D401 MATHEMATICAL BOLD CAPITAL B, from the Mathematical Alphanumeric Symbols block that Unicode added in version 3.1 (2001) so that mathematicians could tell a bold vector v from a plain scalar v in plain text. Because the boldness is baked into the character itself, it survives wherever text survives: a bio field, a caption, a comment, a username box, a tweet.

That is the whole trick behind every bold text generator: it swaps each ordinary letter for its bold twin. There are four complete bold alphabets to pick from. 𝐁𝐨𝐥𝐝 𝐬𝐞𝐫𝐢𝐟 is bold serif, the one most people mean by bold. 𝗕𝗼𝗹𝗱 𝘀𝗮𝗻𝘀 is bold sans-serif, which blends in with the interface fonts of phones and apps and so looks the most like real bold on Instagram or LinkedIn. 𝑩𝒐𝒍𝒅 𝒊𝒕𝒂𝒍𝒊𝒄 and 𝘽𝙤𝙡𝙙 𝙞𝙩𝙖𝙡𝙞𝙘 𝙨𝙖𝙣𝙨 are the two bold italic forms, slanted and heavy. All four cover A–Z and a–z, and the two upright ones also have digits, 𝟎𝟏𝟐𝟑𝟒𝟓𝟔𝟕𝟖𝟗 and 𝟬𝟭𝟮𝟯𝟰𝟱𝟲𝟳𝟴𝟵.

The same block holds more heavy alphabets that have pages of their own: the bold script 𝓑𝓸𝓵𝓭 and the bold Fraktur 𝕭𝖔𝖑𝖉 belong to Cursive Letters (Script Text) and Gothic Letters (Old English Text), and the plain italic 𝐼𝑡𝑎𝑙𝑖𝑐 to Italic Letters (Italic Text). For the wide vaporwave letters see Fullwidth Text, and for the whole family of letter styles start at Letter Emoji & Alphabet Symbols.

Where bold text works: Instagram, Facebook, X, LinkedIn, Discord, WhatsApp

Instagram has no bold button at all, so pasted bold letters are the only way to get a heavy line into a bio, a caption, a comment or a Story text box; 𝗟𝗶𝗻𝗸 𝗶𝗻 𝗯𝗶𝗼 ↓ in the bio is a classic. Your username (the handle after the @) is the exception: handles accept only plain letters, digits, dots and underscores, so bold goes in the display name, not the handle. TikTok, Snapchat and Threads behave the same way: bold in names, bios and captions, plain in the handle.

Facebook posts and comments, X posts and display names, YouTube titles and comments, Pinterest and Reddit titles all take Unicode bold as well, which is why 𝗦𝗔𝗟𝗘 and 𝐍𝐄𝐖 headlines are everywhere in Facebook groups and marketplace listings. LinkedIn has no formatting in posts either, so bold Unicode is how people make a hook line stand out, and recruiters now recognise 𝗢𝗽𝗲𝗻 𝘁𝗼 𝘄𝗼𝗿𝗸 at a glance.

Discord and WhatsApp already have real bold: wrap a word in two asterisks on Discord, like this, or in single asterisks on WhatsApp, like this, and the app renders it bold. Pasted bold letters are still useful there for the places markdown cannot reach: Discord display names, server names, channel names and custom statuses, or a WhatsApp group name and profile name. Telegram and Slack have their own bold formatting too, and Unicode bold works in their names and titles.

Two things never work. Hashtags and @mentions must be plain: #𝘀𝗮𝗹𝗲 is not the same tag as #sale and no search will find it. And the characters depend on the font installed on the reader's device. Every current iPhone, Android, Windows and Mac shows them, but a very old phone or a stripped-down font shows empty boxes, so keep anything essential (a phone number, a link) in plain text.

Accessibility: what a screen reader hears, and the search problem

These letters are honest only to the eye. A screen reader does not see a bold word; it sees a string of mathematical symbols. VoiceOver, TalkBack, NVDA and JAWS read 𝐁𝐨𝐥𝐝 letter by letter as "mathematical bold capital B, mathematical bold small o, mathematical bold small l, mathematical bold small d", and some voices skip the characters altogether, so a blind or low-vision reader hears either noise or nothing where your headline is. Dyslexic readers and anyone relying on a browser's translation also lose the word, because nothing recognises it as the word.

Search engines and site search mostly treat the text the same way. Unicode's compatibility normalisation (NFKC) does map 𝐛𝐨𝐥𝐝 back to bold, and web search engines generally fold the letters that way, but in-app search on Instagram, Discord or LinkedIn usually does not, so a bold name is hard to find by typing it. The sensible rule: use bold letters for one decorative line, a name or a heading, and keep anything someone must read, search for or hear in ordinary text. Where real bold exists (Discord, WhatsApp, Slack, Word, Markdown), prefer it: it is read correctly by every assistive tool.

Bold letters in other alphabets, and how to type bold text

Unicode has bold letters only for Latin, Greek and the digits, because the block was designed for mathematical notation. Searches like bold letters in Arabic or bold text generator Hindi and Bangla have no Unicode answer: there are no bold Arabic, Devanagari or Bengali characters, and a generator that claims to make them is either returning plain text or inserting fake look-alikes. For those scripts, use the app's own bold formatting (asterisks on WhatsApp, the B button in Word) or an image. The same goes for accented letters: there is no bold é or ñ, so a word like café comes out mixed, 𝐜𝐚𝐟é, unless you drop the accent.

Typing bold letters by hand is possible but slow. In Microsoft Word, type the hexadecimal code and press Alt + X: 1D400 Alt+X gives 𝐀, 1D5D4 Alt+X gives 𝗔. On a Mac, Edit → Emoji & Symbols, search "mathematical bold". In LaTeX, \mathbf{B} and \boldsymbol{\beta} produce the same glyphs on paper, though as formatting, not as these characters. On a phone there is no keyboard layout for them, which is why copying from a page like this, or from a bold text generator, is what everyone actually does: the generator does nothing more than the lookup table you see in the grid above.

The code points are tidy. The bold serif alphabet runs from U+1D400 𝐀 to U+1D433 𝐳, capitals first, then small letters, so a bold letter is always its plain letter plus a fixed offset. Bold sans-serif starts at U+1D5D4 𝗔, bold italic at U+1D468 𝑨, bold italic sans-serif at U+1D63C 𝘼, bold digits at U+1D7CE 𝟎 and bold sans-serif digits at U+1D7EC 𝟬. Bold Greek begins at U+1D6A8 𝚨 and includes the final sigma 𝛓, nabla 𝛁, partial 𝛛 and the variant letterforms ϑ-style 𝛝 and ϕ-style 𝛟 that mathematicians need; the Greek alphabet proper is on this page, the variants have their own pages, and the plain Greek letters with their meanings are on Greek Letters.