JavaScript Number parseFloat() Method (original) (raw)

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.

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

a = parseFloat( " 100 " )

console.log( 'parseFloat(" 100 ") = ' + a);

b = parseFloat( "2018@geeksforgeeks" )

console.log( 'parseFloat("2018@geeksforgeeks") = '

`` + b);

c = parseFloat( "geeksforgeeks@2018" )

console.log( 'parseFloat("geeksforgeeks@2018") = '

`` + c);

d = parseFloat( "3.14" )

console.log( 'parseFloat("3.14") = '

`` + d);

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" );

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:

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