# The Excel LN Function

Natural Logarithm

The Logarithm of a number, to a given base, is the power to which the base must be raised to give that number.

The Natural Logarithm of a number, (generally written as Ln(x) or Loge(x) ), is the logarithm to the base e.

Therefore,

If   ex = y   Then   Ln(y) = x
Related Functions:
EXP Function
LOG Function

## Function Description

The Excel LN function calculates the natural logarithm of a given number.

The syntax of the function is:

LN( number )

where the number argument is the positive real number that you want to calculate the natural logarithm of.

## Excel Ln Function Examples

In the example spreadsheet below, the Excel Ln function is used to calculate the natural logarithms of three different numbers, 1, 100 and 0.5:

Formulas:
A
1=LN( 1 )
2=LN( 100 )
3=LN( 0.5 )
Results:
A
10
24.605170186
3-0.693147181

For further examples of the Excel Ln function, see the Microsoft Office website.

## Excel Ln Function Errors

If you get an error from the Excel Ln function, this is likely to be one of the following:

Common Errors
 #NUM! - Occurs if the supplied number argument is negative or zero. #VALUE! - Occurs if the supplied number argument is non-numeric.