This converter maps each letter and digit of your input to Unicode's Mathematical Alphanumeric Symbols block — a complete second copy of the Latin alphabet designed to render as bold, so the result is a real, distinct set of characters rather than CSS-styled text. That's why it pastes as bold anywhere plain text is accepted, including places where actual bold formatting isn't available, like bios and usernames. Because these are technically "symbol" characters rather than letters, screen readers and search engines sometimes read or index them differently than standard text, so it's best reserved for short, decorative snippets rather than large blocks of important content.
It's neither CSS nor a font weight — each character is a completely separate Unicode codepoint that was specifically designed to look bold, so it stays bold no matter what font the destination app uses.
Not always — because these are distinct symbol codepoints rather than the standard alphabet, some accessibility tools and search indexes may skip, mispronounce, or fail to match them the way they would normal text.
Paste it into our companion Unicode to Text Converter, which normalizes these styled Unicode symbols back to their plain-letter equivalents.