# \tau

The τ symbol (Greek small letter tau, U+03C4), written as \tau in LaTeX math mode.

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

## Metadata

| Field | Value |
| --- | --- |
| Topic | [Greek letters](https://texform.dev/latex/topics/greek) |
| Packages | base |
| Allowed mode | math |
| Glyph | τ |
| Unicode | U+03C4 GREEK SMALL LETTER TAU |
| Delimiter | No |

## Syntax

```latex
\tau
```

Takes no arguments.

## Common tasks

### How to write a Greek tau

```latex
\tau
```

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

### How to write a proper time

```latex
d\tau = dt\sqrt{1-v^2/c^2}
```

[Open in Playground](https://play.texform.dev/?input=d%5Ctau+%3D+dt%5Csqrt%7B1-v%5E2%2Fc%5E2%7D)

### How to write a torque

```latex
\tau = r\times F
```

[Open in Playground](https://play.texform.dev/?input=%5Ctau+%3D+r%5Ctimes+F)

## Usage frequency

5.38% of formulas in the measured corpus contain this entry, rank 20 of 474 entries with frequency data.

## In TeXForm

TeXForm parses this entry as a character leaf mapped to U+03C4 (GREEK SMALL LETTER TAU).