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JavaScript Number parseFloat() Method

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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. 



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: 


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



Using parseFloat("3.14") = 3.14 

Example 2: 


// 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. 


let x = parseFloat("3.14");
if (isNaN(x))
    console.log("x is not a number");
    console.log("x is a number");
let y = parseFloat("geeksforgeeks");
if (isNaN(y))
    console.log("y is not a number");
    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);



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.

Last Updated : 23 May, 2023
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