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JavaScript Number parseFloat() Method

Last Updated : 23 May, 2023
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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. 

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.


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