ATAN Function

Excel’s ATAN function returns the arctangent of a number, which is the angle whose tangent is a specified number. In simpler terms, it helps you find the angle in degrees for which the tangent of that angle equals the given number.




numberThe number for which you want to find the arctangent.

How to use

To use the ATAN function, follow these steps:

  1. Start with a number for which you want to calculate the arctangent.
  2. Enter the formula in a cell like this: =ATAN(number)
  3. Replace “number” with the actual value or cell reference containing the number.
  4. Press Enter to get the result, which will be the angle in radians.
  5. To convert the result to degrees, you can multiply it by (180/PI()) because Excel’s ATAN function returns the angle in radians. For example: =ATAN(number) * (180/PI())


Let’s look at a few examples to understand how to use the ATAN function:

Example 1: Find the arctangent of 1. Calculate the angle for which the tangent is 1.

Result: 45 degrees

Example 2: Calculate the arctangent of a cell reference, say B2, which contains the number.

Result: Angle in radians

Example 3: If you want the result in degrees, convert it using the (180/PI()) formula as mentioned earlier.

Result: Angle in degrees

Example 4: Using the ATAN function in a larger formula, e.g., calculating the angle between two points in a coordinate system.

Result: Angle in radians These examples show how you can use the ATAN function to find angles in various scenarios.

Additional information

The ATAN function returns values in radians. If you need the result in degrees, you can use the (180/PI()) conversion formula.

The arctangent function is useful in trigonometry, physics, and engineering to calculate angles based on ratios of sides in right triangles or other geometric situations.

ATAN is the inverse of the TAN function, which calculates the tangent of an angle.

Tomasz Decker is an Excel specialist, skilled in data analysis and financial modeling.