log2() logarithm of a positive integer with base 2 in Python

log2(x) returns logarithm of x with base 2

import math
print(math.log2(2))  # 1.0
print(math.log2(4))  # 2.0
print(math.log2(5))  # 2.321928094887362

Using negative number
For any value less than or equal to 0 , we will get ValueError

import math
print(math.log2(-2))

Above code will generate error.

Use Case: Data Size Calculation: To calculate how many bits are needed to store a number:

print(math.log2(1024) + 1)  # Output: 11.0

Example 2: Error Handling for Negative Numbers

The `log2()` function raises a ValueError if `x` is 0 or negative, as log values are undefined for such inputs.

import math
try:
    print(math.log2(-4))
except ValueError as e:
    print("Error:", e)

Output

Error: math domain error

Example 3: Log2 in Binary Tree Depth Calculation

In binary trees, the depth (number of levels) for a full tree can be calculated using `log2()`.

import math
nodes = 8
depth = math.log2(nodes + 1)
print("Tree depth:", int(depth))

Output

Tree depth: 3

Applications of log2()

Computer Science: To calculate data storage sizes, binary tree depths, and algorithm complexity.
Information Theory: To determine entropy and information content.
Signal Processing: Logarithmic scaling of binary data for processing.

log modf()

Math Functions copysign() Python- Tutorials

Subhendu Mohapatra

Author

🎥 Join me live on YouTube

Passionate about coding and teaching, I publish practical tutorials on PHP, Python, JavaScript, SQL, and web development. My goal is to make learning simple, engaging, and project‑oriented with real examples and source code.

Subscribe to our YouTube Channel here

log2(): Base-2 Logarithmic Calculations for Binary Data

Example 2: Error Handling for Negative Numbers

Example 3: Log2 in Binary Tree Depth Calculation

Applications of log2()

Subhendu Mohapatra