The Excel LOG10 function returns the base 10 logarithm of a number. For example, LOG10(100) returns 2, and LOG10(1000) returns 3.


Get the base-10 logarithm of a number

Return value 

The logarithm


  • number - Number for which you want the logarithm.



Usage notes 

The LOG function allows you to get the base 10 logarithm of a positive number. For example:

=LOG10(100) // returns 2
=LOG10(1000) // returns 3
=LOG10(0.1) // returns -1
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Dave Bruns

Hi - I'm Dave Bruns, and I run Exceljet with my wife, Lisa. Our goal is to help you work faster in Excel. We create short videos, and clear examples of formulas, functions, pivot tables, conditional formatting, and charts.