JavaScript Number parseFloat() Method

Last Updated : 23 May, 2023

JavaScript parseFloat() Method is used to accept the string and convert it into a floating-point number. If the string does not contain a numeral value or If the first character of the string is not a Number then it returns NaN i.e, not a number. It actually returns a floating-point number parsed up to that point where it encounters a character that is not a Number.

Syntax:

parseFloat(Value)

Parameters: This method accepts a single parameter.

value: This parameter obtains a string that is converted to a floating-point number.

Return value: It returns a floating-point Number and if the first character of a string cannot be converted to a number then the function returns NaN i.e, not a number.

Below is an example of the parseFloat() method:

Example 1:

javascript

   let v2 = parseFloat("3.14"); 
  
console.log('Using parseFloat("3.14") = ' + v2);

Output:

Using parseFloat("3.14") = 3.14

Example 2:

javascript

   // It ignores leading and trailing spaces. 
a = parseFloat(" 100 ") 
console.log('parseFloat(" 100 ") = ' + a); 
  
// It returns floating point Number until 
// it encounters Not a Number character 
b = parseFloat("2018@geeksforgeeks") 
console.log('parseFloat("2018@geeksforgeeks") = '
    + b); 
  
// It returns NaN on Non numeral character 
c = parseFloat("geeksforgeeks@2018") 
console.log('parseFloat("geeksforgeeks@2018") = '
    + c); 
  
d = parseFloat("3.14") 
console.log('parseFloat("3.14") = '
    + d); 
  
// It returns only first Number it encounters 
e = parseFloat("22 7 2018") 
console.log('parseFloat("22 7 2018") = '
    + e);
 
  

Output: The parseFloat() function ignores leading and trailing spaces and returns the floating point Number of the string.

parseFloat(" 100 ") = 100  parseFloat("2018@geeksforgeeks") = 2018  parseFloat("geeksforgeeks@2018") = NaN  parseFloat("3.14") = 3.14  parseFloat("22 7 2018") = 22

Example 3: Using the isNaN() function to test whether the converted values are a valid numbers or not.

javascript

   let x = parseFloat("3.14"); 
if (isNaN(x)) 
    console.log("x is not a number"); 
else
    console.log("x is a number"); 
  
let y = parseFloat("geeksforgeeks"); 
if (isNaN(y)) 
    console.log("y is not a number"); 
else
    console.log("y is a number"); 
  
// Difference between parseInt() and parseFloat() 
let v1 = parseInt("3.14"); 
let v2 = parseFloat("3.14"); 
  
console.log('Using parseInt("3.14") = '
    + v1); 
console.log('Using parseFloat("3.14") = '
    + v2);
 
  

Output:

x is a number  y is not a number  Using parseInt("3.14") = 3  Using parseFloat("3.14") = 3.14

Supported Browsers:

Google Chrome 1 and above
Edge 12 and above
Firefox 1 and above
Internet Explorer 3 and above
Safari 1 and above
Opera 3 and above

We have a complete list of JavaScript Number constructor, properties, and methods list, to know more about the numbers please go through that article.