# Log Function

Office 2013 and later
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Returns a Double specifying the natural logarithm of a number.

Syntax

Log( number )

The required number argument is a Double or any valid numeric expression greater than zero.

Remarks

The natural logarithm is the logarithm to the base e. The constant e is approximately 2.718282.

You can calculate base-n logarithms for any number x by dividing the natural logarithm of x by the natural logarithm of n as follows:

Logn(x) = Log(x) / Log(n)

The following example illustrates a custom Function that calculates base-10 logarithms:

```Static Function Log10(X)
Log10 = Log(X) / Log(10#)
End Function

```

## Example

This example uses the Log function to return the natural logarithm of a number.

```Dim MyAngle, MyLog
' Define angle in radians.
MyAngle = 1.3
' Calculate inverse hyperbolic sine.
MyLog = Log(MyAngle + Sqr(MyAngle * MyAngle + 1))

```
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