JavaScript Number parseFloat() Method

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: 

let v2 = parseFloat("3.14");

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

Output:

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");
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.