# Python math.log2() – Logarithm to Base 2

Contents

## Python math.log2()

math.log2(x) function returns the logarithm of x to base 2.

### Syntax

The syntax to call log2() function is

``math.log2(x)``

where

If x is an invalid value, such as a negative value, then log2() raises ValueError.

### Examples

In the following program, we find the logarithm of 8 to base 2, using log2() function of math module.

Python Program

``````import math

x = 8
result = math.log2(x)
print('log2(x) :', result)``````
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Output

``log2(x) : 3.0``

Logarithm of a negative number to base 2.

Python Program

``````import math

x = -1
result = math.log2(x)
print('log2(x) :', result)``````
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Output

``ValueError: math domain error``

Logarithm of infinity.

Python Program

``````import math

x = math.inf
result = math.log2(x)
print('log2(x) :', result)``````
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Output

``log2(x) : inf``

Logarithm of 1024 to base 2.

Python Program

``````import math

x = 1024
result = math.log2(x)
print('log2(x) :', result)``````
Copy

Output

``log2(x) : 10.0``

### Summary

In this Python Examples tutorial, we learned the syntax of, and examples for math.log2() function.

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