Bitcoin symbol

There is no official Bitcoin symbol as of December 2010, however the BTC abbreviation is the most universally accepted form.

Unicode symbol

There is a discussion over which Unicode symbol might be the best suited for bitcoin.

It has lead to the following options:

Refer to the this page on how to type Unicode characters in Microsoft Windows

Proposed character	Pros & Cons	Unicode name	Unicode decimal input	Unicode hex input
฿	Pros: Gives a currency-like look (it is the symbol for an existing currency, the Thai Baht, but other currency symbols often get reused, like the $); displayed correctly on all known OSes Cons: It is already used for the Thai currency, and might confuse people	THAI CURRENCY SYMBOL BAHT		Alt +0E3F
Ⓑ	Pros: Similar to current bitcoin.org logo	CIRCLED LATIN CAPITAL LETTER B		Alt +24B7
ⓑ	Pros: Small b represent the unit bit in computer where capital B is Byte Cons: Small fonts are harder to read	CIRCLED LATIN SMALL LETTER B		Alt +24D1

• ᴃ
• Ƀ
• B⃦
• ␢
• β
• ¤
• Ƅ
• ∄
• ℬ
• ઘ
  • Cons: No visible relation to Bitcoin
• ϭ
  • Cons: No visible relation to Bitcoin
• 
  • Cons: Does not exist in the Unicode standard
• 
  • Cons: Does not exist in the Unicode standard
• ⓢ
• the b'at
  • Pros: Is round like a coin. Contains the B for Bitcoin. Borrows a style widelly associated with the internet. Not used for other meanings.
  • Cons: Not (yet) officially in the Unicode standard.
• A C with 1 and zero inside [[1]]
• A C with a circle and dot inside [[2]]
• ◪

• ☃
  • Cons: Wait, what?

Reference

How to easily type the circled B symbol on a Mac