Last Updated on May 2, 2024 by Roshan Parihar

To find the inverse cosine of the given number in Microsoft Excel, use the Excel ACOS() and pass a number as an argument.

You can get the inverse cosine output in **radian as well as in degree**. However, the default output of the Excel ACOS function value is in radian.

## How to Find Inverse Cosine of a Number in Radian in Excel Sheet?

If you want to find the inverse cosine of the given number, you have to** pass the number** as the argument of the function. Let us take an example of the number -1 to pass as the argument of the function.

1 |
=ACOS(-1) |

Output

The number gives the output as 3.141593 which is the** numeric value of π**. You can get π in Excel using the `PI()`

. The same you can use to convert to the degree using the next example given below.

## Calculate Inverse Cosine in Degree with MS Excel

To calculate the output in degree, you have to **multiply the default output** of the function with `180/PI()`

. You have to use the below-given method to perform the degree conversion.

1 |
=ACOS(-1)*180/PI() |

Output

The above output shows that the degree is 180 after conversion.

## Don’t Use Arguments with Value Other Than -1 to 1

In many cases, you forget to use the argument value to use between -1 and 1. You will **get the error message** as given in the example below.

1 |
=ACOS(5) |

Output

The above example takes 5 as the argument of the function. It gives the error output as #NUM! which indicates that the **argument is incorrect**.