Python math Module Overview

The math module is a built-in Python module for common math work.

It gives you extra functions and constants that are not available as basic language features. Beginners often use it for square roots, rounding, powers, and simple numeric calculations.

This page is an overview. It shows what the module is, how to import it, and which parts are most useful to start with.

Quick example

import math

print(math.sqrt(25))
print(math.ceil(3.2))
print(math.floor(3.8))
print(math.pi)

Expected output:

5.0
4
3
3.141592653589793

Use import math first. Then call functions and constants with the math. prefix.

What the math module is

The math module is part of Python’s standard library.

That means:

You do not need to install it
It is included with Python
You can use it after importing it

The module gives you:

Extra math functions
Useful numeric constants
A simple way to do common calculations

You will often use it for:

Square roots
Rounding up or down
Powers
Trigonometry
Factorials

How to import the math module

Import the module at the top of your file:

import math

After that, use dot notation to access items inside the module:

import math

print(math.sqrt(9))

Output:

3.0

The important idea is:

math is the module name
sqrt is a function inside that module
math.sqrt(9) means “use the sqrt function from the math module”

Common functions beginners use

Here are some of the most common math functions for beginners.

`math.sqrt(x)`

Use math.sqrt(x) to find the square root of a number.

import math

print(math.sqrt(16))

Output:

4.0

For a full guide, see math.sqrt() explained.

`math.ceil(x)`

Use math.ceil(x) to round a number up to the next whole number.

import math

print(math.ceil(3.2))
print(math.ceil(7.0))

Output:

4
7

`math.floor(x)`

Use math.floor(x) to round a number down to the lower whole number.

import math

print(math.floor(3.8))
print(math.floor(7.0))

Output:

3
7

For more examples, see math.ceil() and math.floor() explained.

`math.pow(x, y)`

Use math.pow(x, y) to raise a number to a power.

import math

print(math.pow(2, 3))

Output:

8.0

If you want to compare it with the ** operator, see math.pow() explained.

`math.fabs(x)`

Use math.fabs(x) to get the absolute value as a float.

import math

print(math.fabs(-12))

Output:

12.0

If you want the normal built-in absolute value function, see Python abs() explained.

`math.factorial(n)`

Use math.factorial(n) to calculate a factorial.

A factorial means multiplying a whole number by all smaller positive whole numbers down to 1.

import math

print(math.factorial(5))

Output:

Useful constants

The math module also includes constants.

Constants are values stored in the module that do not change.

`math.pi`

Use math.pi when you need the value of pi.

import math

print(math.pi)

`math.e`

Use math.e for Euler’s number.

import math

print(math.e)

These constants are useful because they give you accurate built-in values instead of making you type them yourself.

When to use math instead of built-in functions

Python already has some built-in numeric tools, so you do not always need the math module.

Built-in functions are often enough for simple tasks, such as:

abs()
round()
min()
max()

Use the math module when:

You need square roots
You need special rounding behavior like ceil() or floor()
You need constants like pi
You need functions that are not built into Python directly

For example:

Use math.sqrt(25) for square roots
Use round() for normal rounding
Use abs() for a simple absolute value
Use math when you need more specialized math tools

Simple example

This example shows:

Importing the module
Using one function
Using one constant

import math

radius = 3
area = math.pi * math.pow(radius, 2)

print("Radius:", radius)
print("Area:", area)

Expected output:

Radius: 3
Area: 28.274333882308138

What this code does:

import math makes the module available
math.pi gives the value of pi
math.pow(radius, 2) squares the radius
The result is used to calculate the area of a circle

Common errors and beginner problems

Here are some common problems when using the math module.

Forgetting to import `math`

This causes a NameError because Python does not know what math is.

print(math.sqrt(16))

Fix:

import math

print(math.sqrt(16))

If this happens, read NameError in Python: causes and fixes.

Using `sqrt()` without `math.`

This also causes a NameError if you imported the module with import math.

import math

print(sqrt(16))

Fix:

import math

print(math.sqrt(16))

Passing invalid values

Some functions only accept certain values.

For example, math.sqrt() does not accept negative numbers in normal real-number math.

import math

print(math.sqrt(-1))

This raises a ValueError.

If you see this problem, read ValueError: math domain error fix.

Shadowing the name `math`

Do not use math as your own variable name.

This can overwrite the module name in your code.

import math

math = 10
print(math.sqrt(16))

This fails because math is now an integer, not the module.

What to learn next

After this overview, the best next step is to learn one function at a time.

Good next topics include:

math.sqrt() for square roots
math.ceil() and math.floor() for rounding
math.pow() for exponent calculations
Built-in numeric functions like abs() and round()
Error pages if your code raises NameError or ValueError

FAQ

Do I need to install the math module?

No. The math module comes with Python, so you only need to import it.

Why does Python say math is not defined?

You probably forgot to import math, or you used the name before importing it.

What is the difference between `math.pow()` and `**`?

Both do exponent calculations, but ** is an operator and math.pow() is a function that returns a float.

Can I use `math.sqrt()` on negative numbers?

No for normal real-number math. It raises a ValueError. Complex numbers use different tools.