How to convert binary to decimal in JavaScript easily

By Saruque Ahamed Mollick

Converting a number from binary to decimal is a mathematical approach. We can find several mathematical algorithms to find out the decimal value of a binary number and vice versa. But implementation of those algorithms in coding just to convert a binary number to decimal number of convert a decimal number is just ridiculous.

I love JavaScript because like other popular languages JavaScript also have a ready-made inbuilt function which is able to convert strings to numbers. This method will be very useful for us to convert a binary number to decimal.

Convert Binary to Decimal In JavaScript

Convert a binary number to a decimal number using JavaScript will be easiest for us if we use


This method can take two parameters. In the first parameter, we can pass any string. So we can pass number string and this method will convert the string to a number.
Just like this one:
If we pass “1457” this method will convert it into a number like 1457.
Now, In the second parameter, we can pass the base. That means in which number system the string is. eg, decimal, binary, hexadecimal etc.

Now you can easily predict what I am going to do to convert a decimal number to a binary number.

The default number system in which parseInt() method returns its value is decimal.

var binary = "101101";
var decimal = parseInt(binary, 2);

This will give you the output in an alert box.

The full example in HTML code,

<!DOCTYPE html>
  <script type="text/javascript">
    var binary = "101101";
var decimal = parseInt(binary, 2);

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