Returns the logarithm of a number to the base you specify.
Syntax
LOG(number,base)
Number is the positive real number for which you want the logarithm.
Base is the base of the logarithm. If base is omitted, it is assumed to be 10.
Example
The example may be easier to understand if you copy it to a blank worksheet.
How to copy an example
 Create a blank workbook or worksheet.
 Select the example in the Help topic.
Note Do not select the row or column headers.
Selecting an example from Help
 Press CTRL+C.
 In the worksheet, select cell A1, and press CTRL+V.
 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.

A 
B 
Formula 
Description (Result) 
=LOG(10) 
Logarithm of 10 (1) 
=LOG(8, 2) 
Logarithm of 8 with base 2 (3) 
=LOG(86, 2.7182818) 
Logarithm of 86 with base e (4.454347) 
