# How to calculate logarithm in Python

To calculate the logarithm of a number with the python language we use the log () function of the math library.

**math.log(x,base)**

- The first argument in input (x) is the real number of the logarithm.
- The second argument (b) is optional and it indicates the
**basis of the logarithm**.

The function returns in output (y) the logarithm on base b of the number x.

If the base is not specified, the log () function calculates the **natural logarithm** of the number x.

**Note**. The log () function is contained in the math module. So, to use it in a script, you must first import it using the import or from import statement.

## Examples of calculation

__Example 1__

In this script the **log()** function calculates the natural logarithm of 10.

from math import log

log(10)

The output result is

2.302585092994046

So the exponential e^{2.302585092994046} is equal to 10.

__Example 2__

This script calculates the logarithm of 100 on a 10 basis.

import math

log(100,10)

The output result is

2.0

The power of the number 10^{2} is equal to 100. So the log of one hundred on a ten basis is two.

**Report an error or share a suggestion to enhance this page**