How to Format a Number to a Specific Number of Decimal Places in JavaScript

In this tutorial, we are going to learn about formatting a number to specific decimal places in JavaScript using the toFixed() method.

Consider that we have a number like this.

const num  = 123.1390;

Now, we need to format the above number according to specific decimal places like 123.12 or 123.139.

Using toFixed() Method

The toFixed() method formats a number and returns the string representation of a number. Be default the toFixed() method removes the fractional part.

It also accepts the optional argument called digits, which means we need to specify the number of digits after the decimal point.

Let’s see an example:

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const num  = 123.1390

            // fractional part is removed

console.log(num.toFixed()); // "123"

You may also like: How JavaScript Actually Works: Part 1.

Now, you can see that our number is converted to a string representation. Because of this, we need to convert the string back to a number by adding + operator.

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console.log(+num.toFixed()); // 123

Formatting Number to Two Decimal places

To format a number to two decimal places we need to pass 2 as an argument to the toFixed() method.

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const num  = 123.1390

console.log(+num.toFixed(2)); // 123.13

Similarly, we can format a number according to our needs like this:

const num  = 123.1390

          // 1 decimal place

console.log(+num.toFixed(1)); // 123.1

          // 2 decimal places

console.log(+num.toFixed(2)); // 123.13

          // 3 decimal places

console.log(+num.toFixed(3)); // 123.139

Further Reading

• Guide to New JavaScript Features Introduced at Google I/O 2019.
• An Introduction to JavaScript/ES6 Arrow Functions.
• Comparing React With ES5 vs. React With ES6.