Calculates the natural logarithm of a number. Natural logarithms are based on the constant e (2.71828182845904).

The natural logarithm of a number.

Mathematical functions

Log(number)

Exp, Log10

<h3>Log Example</h3>

<cfif IsDefined("FORM.number")>
   <cfoutput>
      <p>Your number, #FORM.number#
      <br>#FORM.number# raised to the E power: #exp(FORM.number)#
      <cfif FORM.number LTE 0><br>Enter a positive real number to get its 
natural logarithm
         <cfelse><br>The natural logarithm    of #FORM.number#: #log(FORM.number)#
      </cfif>
      <cfif FORM.number LTE 0><br>Enter a positive real number to get its 
logarithm to base 10
         <cfelse><br>The logarithm of #FORM.number# to base 10: 
#log10(FORM.number)#
      </cfif>
   </cfoutput>
</cfif>
<cfform action = "log.cfm">
Enter a number to see its value raised to the E power, its natural logarithm, 
and the logarithm of number to base 10.
<cfinput type = "Text" name = "number" message = "You must enter a number"
validate = "float" required = "No">
<input type = "Submit" name = "">
</cfform>