Parse a String with Commas to a Number in JavaScript

Parse a String with Commas to a Number #

To parse a string with commas to a number:

1. Use the replace() method to remove all the commas from the string.
2. The replace method will return a new string containing no commas.
3. Convert the string to a number.

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const str = '12,000,000.50';

const num = parseFloat(str.replace(/,/g, ''));

console.log(num); // 👉️ 123000000.5

In the code snippet we used the String.replace method to remove all the commas from the string.

The forward slashes / / mark the start and end of the regular expression.

In our regex, we only match a comma. Notice that we use the g (global) flag, because we want to match all occurrences of a comma in the string and not just the first one.

If you ever need help reading a regular expression, check this regex cheatsheet from MDN out.

The last step is to call the parseFloat function on the result.

The parseFloat function takes a string as a parameter and returns a floating point number.

If the parseFloat function cannot convert the string to a number (the string contains non-numeric characters), it returns NaN (not a number).

Here are some examples of using the parseFloat function.

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console.log(parseFloat('100')); // 👉️ 100
console.log(parseFloat('100.5')); // 👉️ 100.5
console.log(parseFloat(10.5)); // 👉️ 10.5
console.log(parseFloat('a123')); //👉️ NaN

If you are looking to avoid using regular expressions, you can use the String.replaceAll method instead of replace.

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const str = '12,000,000.50';

const num = parseFloat(str.replaceAll(',', ''));

console.log(num); // 👉️ 123000000.5

This code snippet achieves the same result, however instead of passing a regex as the first parameter, we pass a string containing a comma.

The second parameter is the replacement for each match, just like with the replace method.

Further Reading #

• How to Parse Float with 2 Decimal places in JavaScript
• Convert Comma Separated String to Numeric Array in JS
• Extract a Number from a String in JavaScript
• Check if String is a Valid Number in JavaScript
• Check if String contains at least one Number in JavaScript