Excel LN Function

The natural logarithm function is the inverse of the exponential function and is used to model exponential decay. The function is equivalent to log base e of a number, where e is Euler's number. 

Examples

=LN(1) // returns 0
=LN(e) // returns 1
=LN(e^2) // returns 2

The equivalent form of the natural logarithm function is given by:

=LN(number)=LOG(number,e) // Where e ≈ 2.7128 or EXP(1)

Graphs

Below is a graph of the natural log logarithm:

The natural logarithm function and exponential function are the inverse of each other, as you can see in the graph below:

This inverse relationship can be represented with the formulas below, which the input to the LN function is the output of the EXP function:

= LN(EXP(1)) // returns 1
= LN(EXP(2)) // returns 2
= LN(EXP(n)) // returns n

See wumbo.net for a more detailed explanations of key math concepts and formulas. 

Notes

• The natural logarithm function can be defined as the area under a hyperbola. 
• The function is used in applications relating to compound interest.