# \phi

The ϕ symbol (Greek phi symbol, U+03D5), written as \phi in LaTeX math mode.

https://texform.dev/latex/symbols/phi

## Metadata

| Field | Value |
| --- | --- |
| Topic | [Greek letters](https://texform.dev/latex/topics/greek) |
| Packages | base |
| Allowed mode | math |
| Glyph | ϕ |
| Unicode | U+03D5 GREEK PHI SYMBOL |
| Delimiter | No |

## Syntax

```latex
\phi
```

Takes no arguments.

## Common tasks

### How to write a Greek phi

```latex
\phi
```

[Open in Playground](https://play.texform.dev/?input=%5Cphi)

### How to write an Euler totient

\phi is the straight glyph; \varphi is the loopy variant used for totients.

```latex
\varphi(n)
```

[Open in Playground](https://play.texform.dev/?input=%5Cvarphi%28n%29)

### How to write a golden-ratio phi

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

[Open in Playground](https://play.texform.dev/?input=%5Cphi%3D%5Cfrac%7B1%2B%5Csqrt%7B5%7D%7D%7B2%7D)

## Usage frequency

5.41% of formulas in the measured corpus contain this entry, rank 18 of 474 entries with frequency data.

## In TeXForm

TeXForm parses this entry as a character leaf mapped to U+03D5 (GREEK PHI SYMBOL).