PythonHow-ToBeginner · 3 min read

How to Truncate Float to 2 Decimal Places in Python

To truncate a float to 2 decimal places in Python, you can multiply the number by 100, use math.trunc() to remove extra decimals, then divide by 100. Alternatively, convert the float to a string with slicing or use decimal.Decimal for precise control.

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Syntax

Here is the basic syntax to truncate a float to 2 decimal places using math.trunc():

import math: imports the math module.
math.trunc(value * 100) / 100: multiplies the float by 100, truncates the decimal part, then divides back by 100.

python

import math

truncated_value = math.trunc(your_float * 100) / 100

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Example

This example shows how to truncate the float 3.14159 to 2 decimal places using math.trunc() and also using string slicing.

python

import math

number = 3.14159

# Using math.trunc
truncated = math.trunc(number * 100) / 100
print(truncated)  # Output: 3.14

# Using string slicing
str_num = str(number)
if '.' in str_num:
    integer_part, decimal_part = str_num.split('.')
    truncated_str = integer_part + '.' + decimal_part[:2]
    truncated_float = float(truncated_str)
else:
    truncated_float = float(str_num)
print(truncated_float)  # Output: 3.14

Output

3.14 3.14

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Common Pitfalls

Many people try to use round() to truncate, but round() rounds the number instead of truncating it. Also, converting floats to strings and back can cause errors if not handled carefully.

Using format() or f-strings only formats the output but does not change the actual float value.

python

import math

number = 3.149

# Wrong: round() rounds instead of truncates
print(round(number, 2))  # Output: 3.15 (not truncated)

# Right: truncation
truncated = math.trunc(number * 100) / 100
print(truncated)  # Output: 3.14

Output

3.15 3.14

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Quick Reference

Method	Description	Example Output for 3.149
math.trunc()	Truncates by removing decimals after multiplying	3.14
String slicing	Convert to string and cut decimals	3.14
round()	Rounds number, not truncates	3.15
format()/f-string	Formats output, does not change value	'3.15' as string

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Key Takeaways

Use math.trunc(value * 100) / 100 to truncate a float to 2 decimals.

round() rounds numbers and does not truncate.

String slicing can truncate but requires careful conversion.

Formatting with f-strings changes display, not the float value.

Truncation removes decimals without rounding up.