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How To Convert String To Number In Javascript


Javascript parseInt() is an inbuilt function that convert string to number(integer). Javascript parseFloat() is an inbuilt method that converts the string to floating number. So, there are other methods in Javascript that convert to number.

  1. parseInt()
  2. parseFloat().

How To Convert String To Number In Javascript

Let us take an example of Javascript on Node.js.

Create one file called the node.js and add the following code.

const data = Number('48155');


Now, go to the terminal and start the node.js server.

node server

It will also take care of the decimal as well.

A Number is a wrapper object that can perform many operations. If we use the constructor (new Number("48155")) it returns us a Number object instead of a number value, so pay attention.

How To Convert A String To A Number In Javascript

Javascript parseInt()

The parseInt() method converts a string into an integer (a whole number). It accepts two arguments. The first argument is the string to convert.

// server.js

let text = '21px';
let integer = parseInt(text, 10);


It will log the 21 value.

Javascript parseFloat()

The parseFloat() method converts a string into a point number (a number with decimal points). You can even pass in strings with random text in them.

// server.js

let text = '3.14pie';
let integer = parseFloat(text, 10);


+ Unary Operator

One “trick” is to use the unary operator + before the string. The unary plus is used when your string is already in the form of an integer.

// server.js

let x = 5+"1000";


The output will be the 51000.


Similar to the + unary operator, but returns the integer part.

// server.js

let floor = Math.floor("1000.51");

If your string is or might be a float and you want an integer then it might help you. 

The answer of above is 1000.

#Browser Compatibility

All three methods work in all modern browsers, and IE6 and up.

Finally, How To Convert String To Number In Javascript example tutorial is over.

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