# Excel LN Function

Summary

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

Purpose

Get the natural logarithm of a number

Return value

The natural logarithm

Syntax

=LN (number)

Arguments

**number**- A number to take the natural logarithm of.

Usage notes

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

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

### 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:

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.