# ATAN function: Description, Usage, Syntax, Examples and Explanation

## What is ATAN function in Excel?

ATAN function is one of the Math and Trig functions in Microsoft Excel that returns the arctangent, or inverse tangent, of a number. The arctangent is the angle whose tangent is number. The returned angle is given in radians in the range -pi/2 to pi/2.

## Syntax of ATAN function

ATAN(number)

The ATAN function syntax has the following arguments:

**Number:**The tangent of the angle you want.

## ATAN formula explanation

To express the arctangent in degrees, multiply the result by 180/PI( ) or use the DEGREES function.

## Example of ATAN function

Steps to follow:

1. Open a new Excel worksheet.

2. Copy data in the following table below and paste it in cell A1

Note: For formulas to show results, select them, press F2 key on your keyboard and then press Enter.

You can adjust the column widths to see all the data, if need be.

Formula |
Description |
Result |

=ATAN(1) | Arctangent of 1 in radians, pi/4 | 0.785398163 |

=ATAN(1)*180/PI() | Arctangent of 1 in degrees | 45 |

=DEGREES(ATAN(1)) | Arctangent of 1 in degrees | 45 |