ACOS Function in Excel: Syntax, Examples and Free Practice

By Rinkesh Shah, founder of Cellgrids.

ACOS is an Excel Math & Trig function. Returns the arccosine of a number, in radians.

ACOS syntax

=ACOS(number)

ACOS is used in financial models and engineering-style calculations where precise numeric work is needed.

Open the live Excel-style spreadsheet and try ACOS yourself. No Excel install or sign-up needed to start.

What does the ACOS function do in Excel?

Returns the arccosine of a number, in radians.

What is the syntax of ACOS in Excel?

The syntax is =ACOS(number). number: A number to use in the calculation.

Where can I practice ACOS online for free?

Open the free live spreadsheet on Cellgrids and try ACOS yourself. No Excel install is needed and you can start without signing up.