How to get the Length of a Number in JavaScript

Get the Length of a Number in JavaScript #

To get the length of a number, call the toString() method on the number to convert it to a string and access the length property on the string. The length property returns the number of code units in the string.

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const integer = 123456;
const float = 123.45;

console.log(integer.toString().length); // 👉️ 6

console.log(float.toString().length); // 👉️ 6

In both of the examples, we used the Number.toString method to convert the number to a string.

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const integer = 123456;

const str = integer.toString();
console.log(str); // 👉️ '123456'

After we convert the number to a string, we can safely access the string's length property.

Note that when trying to get the length of a float number the length property also counts the dot . character.

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const float = 123.45;

const withDot = float.toString().length;
console.log(withDot); // 👉️ 6

const withoutDot = float.toString().length - 1;
console.log(withoutDot); // 👉️ 5

In case you don't like using the Number.toString method, you can use a template literal.

To get the length of a number, wrap the number in a template literal to convert it to a string and access the length property on the string, e.g. ${100}.length.

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const integer = 123456;

const intLen = `${integer}`.length;
console.log(intLen); // 👉️ 6

const float = 123.45;

const floatLength = `${float}`.length;
console.log(floatLength); // 👉️ 6

In this example we achieve the same result, by using a template literal to convert the number into a string.

The ${} part of the template literal allows us to embed an expression, which gets evaluated.

A perhaps more direct and straight forward approach is to simply pass the number to the String object.

To get the length of a number, pass the number as a parameter to the String object to convert it to a string and access the length property on the string, e.g. String(1500).length.

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const integer = 123456;

const intLen = String(integer).length;
console.log(intLen); // 👉️ 6

const float = 123.45;

const floatLength = String(float).length;
console.log(floatLength); // 👉️ 6

The String object converts the type of the passed in parameter to a string, on which we can access the length property.

Further Reading #

• Split a Number into an Array in JavaScript
• How to sort a Set in JavaScript