Python How to Convert Float to Integer Easily

In Python, you can convert a float to an integer by using the int() function, like int(3.7), which will return 3.

Examples

Input3.7

Output3

Input-2.9

Output-2

Input0.0

Output0

How to Think About It

To convert a float to an integer, think about removing the decimal part. Using the int() function in Python simply cuts off everything after the decimal point without rounding, giving you the integer part.

Algorithm

1

Get the float number as input.

2

Use the <code>int()</code> function to convert the float to an integer.

3

Return or print the integer result.

Code

python

float_num = 3.7
int_num = int(float_num)
print(int_num)

Output

3

Dry Run

Let's trace converting 3.7 to an integer using int()

1

Start with float

float_num = 3.7

2

Convert to int

int_num = int(3.7) which becomes 3

3

Print result

print(3) outputs 3

Step	Value
Initial float	3.7
After int()	3
Output	3

Why This Works

Step 1: int() removes decimal

The int() function cuts off the decimal part without rounding.

Step 2: Conversion returns integer

The result is a whole number type, not a float.

Alternative Approaches

Using math.floor()

python

import math
float_num = 3.7
int_num = math.floor(float_num)
print(int_num)

This always rounds down to the nearest integer, unlike int() which truncates.

Using round() and then int()

python

float_num = 3.7
int_num = int(round(float_num))
print(int_num)

This rounds the float to the nearest integer before converting.

Complexity: O(1) time, O(1) space

Time Complexity

Conversion with int() is a simple operation that takes constant time.

Space Complexity

No extra memory is needed besides the output integer.

Which Approach is Fastest?

int() is fastest for truncation; math.floor() and round() add slight overhead.

Approach	Time	Space	Best For
int()	O(1)	O(1)	Simple truncation without rounding
math.floor()	O(1)	O(1)	Always rounding down
round() + int()	O(1)	O(1)	Rounding to nearest integer