What is Unicode bold actually made of?

It is the Mathematical Alphanumeric Symbols block of Unicode, a set of separate code points that happen to look bold. Because they are real characters, not a style applied to normal letters, they keep their look when pasted as plain text.

Will it work the same on every app?

The output is the same Unicode wherever you paste it. What changes is whether the destination font has those glyphs. Most modern apps and phones render them, but the odd older device or custom font falls back to plain or boxed characters.

Is it bad for accessibility or search?

Yes, to a degree. Screen readers stumble over the math glyphs and search engines do not treat them as the plain letters, so do not put your name or important keywords in Unicode bold. Use it for light emphasis only.

Bold Text Generator

Type your text and copy Unicode bold, the look-alike glyphs that carry their styling into apps with no formatting like X, LinkedIn and Instagram.

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Paste here

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Your converted, copy-ready text appears here.

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Runs entirely in your browser. Your text never leaves your device.

How Markdown maps to Unicode

Feature	Markdown	Unicode
Bold	x	𝐛𝐨𝐥𝐝 (Unicode)
Italic	x	𝑖𝑡𝑎𝑙𝑖𝑐 (Unicode)

Common gotchas

This does not make real bold. It swaps each letter for a Unicode Mathematical Alphanumeric glyph that already looks bold, so the look survives a plain-text paste anywhere.
Only A to Z, a to z and the digits 0 to 9 have bold glyphs. Spaces, punctuation, emoji and accented or non-Latin letters pass through unchanged, so a fully styled line can look slightly mixed.
Screen readers read these math glyphs letter by letter or skip them, and a few older fonts show blank boxes instead, so keep it to a heading or a word or two rather than a whole paragraph.
Italic has no digit glyphs in Unicode, so numbers stay plain when you pick italic.

Frequently asked

What is Unicode bold actually made of?: It is the Mathematical Alphanumeric Symbols block of Unicode, a set of separate code points that happen to look bold. Because they are real characters, not a style applied to normal letters, they keep their look when pasted as plain text.
Will it work the same on every app?: The output is the same Unicode wherever you paste it. What changes is whether the destination font has those glyphs. Most modern apps and phones render them, but the odd older device or custom font falls back to plain or boxed characters.
Is it bad for accessibility or search?: Yes, to a degree. Screen readers stumble over the math glyphs and search engines do not treat them as the plain letters, so do not put your name or important keywords in Unicode bold. Use it for light emphasis only.