Phi Symbol

Φ ϕ

The phi symbol (Φ / ϕ) is a letter of the Greek alphabet. This page covers its meaning across mathematics, science, and engineering, its Unicode code point, TeX command, and Windows Alt codes — and you can copy and paste the phi symbol with one click.

Uppercase Phi Symbol (Φ)

Symbol	Format	Data
Φ	Unicode	U+03A6
Φ	HTML	Φ
Φ	CSS	\03a6
Φ	JavaScript	\u03A6
$\Phi$	TeX	\Phi
	SVG	Download ↓
	Image	Download ↓

Also known as: phi, uppercase phi, big phi, greek phi, circle with line, normal cdf symbol, flux symbol, fi.

The Greek capital letter Phi (Φ) commonly denotes the cumulative distribution function of the standard normal distribution in probability and statistics. It is also used for a flux in physics, a homomorphism in algebra, and the Euler phi function in number theory, though the latter is more often lowercase. In geometry it may represent an angle, such as the dihedral angle between two planes.

\Phi(z) = \frac{1}{\sqrt{2\pi}} \int_{-\infty}^{z} e^{-t^2/2} \, dt

Lowercase Phi Symbol (ϕ)

Symbol	Format	Data
ϕ	Unicode	U+03D5
ϕ	HTML	ϕ
ϕ	CSS	\03d5
ϕ	JavaScript	\u03D5
$\phi$	TeX	\phi
	SVG	Download ↓
	Image	Download ↓

Also known as: greek phi, phi letter, golden ratio symbol, golden mean symbol, totient function, euler totient, fee, phi sign, angle symbol phi.

The Greek letter phi (ϕ) has several established uses in mathematics. It most famously denotes the golden ratio (1 + √5)/2, approximately 1.618, but it also represents Euler's totient function in number theory and a generic angle in geometry and physics. In TeX the closed glyph ϕ is produced by \phi and the open glyph φ by \varphi, with no difference in meaning.

\phi = \frac{1 + \sqrt{5}}{2}

Phi Symbol Alt Codes

On Windows, hold Alt and type the code on the numeric keypad, then release Alt. Num Lock must be on.

Alt Code	Case	Symbol
Alt232	Uppercase	Φ

Codes without a leading zero are legacy OEM codes; they depend on a US English Windows code page.

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Phi Symbol — Φ Greek Capital Letter Phi, ϕ Greek Phi Symbol