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𝐀

mathematical bold capital a

Mathematical Bold Capital A

The Unicode bold A, 𝐀, is a separate character: use Word’s hexadecimal input when you need that exact mathematical form. In equations, it marks a letter style that can distinguish one quantity from another; outside math, people also use it to imitate bold text in plain-text posts. Text tools may treat it differently from ordinary A.

Text symbol

What 𝐀 means

Type 1D400, then press AltX.

Enter the hexadecimal value without the U prefix; this converts it to the character. If it appears as a box, the selected font may not include its glyph. Other apps use different input methods.

What does mathematical bold A mean in a formula?

It marks a distinct mathematical letter; the formula sets its exact role.

Mathematical publishing used letter styles to distinguish variables. A 1999 proposal sought separate characters so formulas and plain-text searches could preserve those distinctions.

Why does 𝐀 appear in plain-text posts?

It can imitate bold when an app offers no text styling.

A 2026 draft of Unicode’s math guidance describes this as a workaround or playful use on social media. In a formula it is notation; in a bio or caption it may be decorative styling.

In equations it is mathematical notation; in a bio or caption it reads as stylized lettering.

For text that must match plain A, use A with ordinary bold formatting.

Part of the collection

𝐁

Bold Letters (Bold Text)

What it means when someone sends it to you

2 readings

A mathematical quantity whose exact role depends on the notation.

Don't confuse it with

Latin Capital Letter A

Plain Latin capital A. 𝐀 is a separate mathematical character, though compatibility normalization can reduce it to A.

Questions people ask

What is the difference between 𝐀 and A?

They are separate characters. 𝐀 is mathematical bold; A is an ordinary Latin capital. Compatibility normalization can map the styled character to plain A.

Why did 𝐀 turn into A?

A compatibility-normalization step may have changed it. NFKC can fold this math-style character to ordinary A, losing the bold distinction.

Why is 𝐀 showing as a box?

The selected font may lack this glyph. Choose a font that supports mathematical alphanumeric characters; the character itself remains 𝐀.

How to type or find 𝐀

Search it as: bold A · unicode bold A · math bold A · bold A text · bold A character
Shows up in: Anything that takes text · its shape is whatever your font draws

Windows (Word)

⎇Alt+XType 1D400, then AltX to get 𝐀.

Windows

⊞Win+Rrun charmap for the full table, or use the emoji picker's Ω symbols tab (Win .).

macOS

⌃Control+⌘Command+␣SpaceOpen the character viewer and search “mathematical bold capital a”.

Linux

⎈Ctrl+⇧Shift+UType 1d400, then Enter or Space.

HTML

𝐀

CSS

\1D400

Microsoft Word

Microsoft’s 2026 Word instructions: type 1D400 without the U prefix, then press AltX.

Codes and encoding1 code points

HTML decimal

𝐀

HTML hex

𝐀

CSS content

content: "\1D400";

Each escape is closed by the next backslash; a trailing space is needed before a literal hex digit.

URL encoded

%F0%9D%90%80

On screen

Code points

JS .length

UTF-8 bytes

A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.

Mathematical Bold Capital A

What 𝐀 means