Phi Symbol
About Phi Symbol
φ is the Phi Symbol, the lowercase form of the 21st letter of the Greek alphabet (Φ / φ). The Phi Symbol φ is among the most common Greek letters in scientific and technical literature, frequently used for It denotes the golden ratio, phase angle, and Euler's totient function in number theory.
【Pronunciation】 In English, φ is most often pronounced FIE or FEE (IPA: /faɪ, fiː/). This is simply the anglicized name of the Greek letter.
The lowercase Phi Symbol φ is written as a distinct Greek glyph and is assigned codepoint U+03C6 in the Greek and Coptic Unicode block. In plain or sans-serif fonts it can be mistaken for the Latin letter f or Φ, so verify the typeface or context.
【Historical Origin】 Phi derives from the Phoenician letter qoph and is significant in both aesthetics and engineering.
【Common Uses】 φ is highly active across disciplines: It denotes the golden ratio, phase angle, and Euler's totient function in number theory. It often appears alongside the uppercase Sigma Σ and lowercase Sigma σ in formulas, papers, and engineering drawings.
How to Type Phi Symbol
Windows Input
Method 1: Hold Alt and type 966 on the numeric keypad, then release Alt to get φ.
Mac Input
Method 2: Press Control + Command + Space to open the Character Viewer, search for 'greek' or 'Phi Symbol', then select φ.
HTML/CSS Input
Method 3: HTML: φ or φ or φ; CSS: content: "\03C6";
LaTeX Input
Method 4: Use the \phi command in LaTeX math mode to produce φ.
Phi Symbol FAQ
How is φ pronounced?
The English pronunciation of φ is FIE or FEE (IPA: /faɪ, fiː/). It is the anglicized name of the Greek letter, used directly rather than described as 'lowercase φ'.
What is the difference between φ and the Latin letter f or Φ?
φ (U+03C6) is a Greek lowercase letter, whereas f or Φ is a Latin letter; their codepoints and glyphs differ. In a proper typeface φ and f or Φ are clearly distinct, but in plain text or sans-serif fonts they can be confused, so rely on context.
How do I type φ in Word, web pages, and LaTeX?
On Windows use Alt+966 on the numeric keypad; on Mac open the Character Viewer and search 'greek' or 'Phi Symbol'; on the web use the HTML entity φ; in LaTeX use \phi. For bulk use, copy φ directly from this page.