In this tutorial, we will look at how to convert a string in Python to a float value, that is, float
datatype with the help of some examples.
How to convert string to float in Python?

You can use the Python built-in float()
function to convert a string to a float value in Python. The following is the syntax –
# convert string s to float float(s)
It returns the passed string as a floating-point value. Note that if the passed string does not represent a numeric value, it will raise an error.
Examples
Let’s look at some examples of using the above syntax to convert a string to a floating-point value.
First, let’s apply the float()
function on a string containing a real number with a decimal part, for example, “150.75”.
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# string storing a float number s = "150.75" # convert string to float num = float(s) # display the number and its type print(num) print(type(num))
Output:
150.75 <class 'float'>
You can see that we get 150.75
as a float value.
What happens if you pass an integer number as a string to the float()
function? Let’s find out.
# string storing an integer s = "150" # convert string to float num = float(s) # display integer and its type print(num) print(type(num))
Output:
150.0 <class 'float'>
We get 150.0
as a float point number after conversion.
If you want to convert the above string to an integer in Python, use the int()
function instead.
# string storing an integer s = "150" # convert string to int num = int(s) # display number and its type print(num) print(type(num))
Output:
150 <class 'int'>
We get the string as an integer.
What happens if you pass a non-numeric string to the float()
function? Let’s find out.
# string with text s = "cat" # convert string to float num = float(s) # display number and its type print(num) print(type(num))
Output:
--------------------------------------------------------------------------- ValueError Traceback (most recent call last) Input In [4], in <module> 2 s = "cat" 3 # convert string to float ----> 4 num = float(s) 5 # display number and its type 6 print(num) ValueError: could not convert string to float: 'cat'
As expected, we get an error because the passed string cannot be represented as a floating-point number.
You might also be interested in –
- Extract Numbers From String in Python
- Python – Check if String Contains Only Numbers
- Python Tuple to Integer
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