Microsoft KB Archive/214116

= XL: Formulas to Find the Log and Inverse Log of a Number =

Article ID: 214116

Article Last Modified on 1/24/2007

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APPLIES TO


 * Microsoft Excel 2000 Standard Edition
 * Microsoft Excel 2002 Standard Edition
 * Microsoft Excel 97 Standard Edition
 * Microsoft Excel 2001 for Mac
 * Microsoft Excel 98 for Macintosh

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This article was previously published under Q214116





SUMMARY
Microsoft Excel has built-in functions to calculate the logarithm of a number with a specified base, the logarithm with base 10, and the natural logarithm. To calculate the inverse log of a number in the first two cases, raise the base to the power of the value returned by the particular logarithm function being used. To find the inverse natural log, use the EXP function.



MORE INFORMATION
You can use the formulas in the following table to perform logarithmic and inverse log operations:   Formula       Operation              Example            Result -  =LOG(n,b)     Log base b of n        =LOG(8,2)          3

=(b)^(x)     Inverse log of the     =2^3               8 number x, base b

=LOG10(n)    Log base 10 of n       =LOG10(100)        2

=10^(x)      Inverse log of the     =10^2              100 number x, base 10

=LN(n)       Natural log of n       =LN(100)           4.6051702

=EXP(x)      Inverse natural        =EXP(4.6051702)    100 log of the number x In the preceding table,  is a variable that is either a value or the address of a cell containing a value,   (in the first function) is the base with which the logarithm is calculated, and   is a variable representing the result of the log function being used.

NOTE: Unless a different value or cell address is specified, the default value for the base is 10.

Additional query words: revlog log10 arc Anti AntiLog anti-log \* 5x XL2000 xl2002 xl2001 xl98 xl97

Keywords: kbhowto KB214116

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