This article describes the formula syntax and usage of the IMLN function (function: A prewritten formula that takes a value or values, performs an operation, and returns a value or values. Use functions to simplify and shorten formulas on a worksheet, especially those that perform lengthy or complex calculations.) in Microsoft Excel.
Description
Returns the natural logarithm of a complex number in x + yi or x + yj text format.
Syntax
IMLN(inumber)
The IMLN function syntax has the following arguments (argument: A value that provides information to an action, an event, a method, a property, a function, or a procedure.):
 Inumber Required. A complex number for which you want the natural logarithm.
Remarks
 Use COMPLEX to convert real and imaginary coefficients into a complex number.
 The natural logarithm of a complex number is:
Example
The example may be easier to understand if you copy it to a blank worksheet.
How do I copy an example?
 Select the example in this article. If you are copying the example in Excel Online, copy and paste one cell at a time.
Important: Do not select the row or column headers.
Selecting an example from Help
 Press CTRL+C.
 Create a blank workbook or worksheet.
 In the worksheet, select cell A1, and press CTRL+V. If you are working in Excel Online, repeat copying and pasting for each cell in the example.
Important: For the example to work properly, you must paste it into cell A1 of the worksheet.
 To switch between viewing the results and viewing the formulas that return the results, press CTRL+` (grave accent), or on the Formulas tab, in the Formula Auditing group, click the Show Formulas button.
After you copy the example to a blank worksheet, you can adapt it to suit your needs.

A 
B 
Formula 
Description (Result) 
=IMLN("3+4i") 
Natural logarithm of 3+4i (1.609438 + 0.927295i) 
