In English, it’s essential to capitalize the first letter of a sentence. JavaScript has built-in methods to help us with this.

In this article we will look at three different ways to check if the first letter of a string is upper case and how to capitalize it.

Check if First Letter Is Upper Case in JavaScript

We can check if the first of a letter a string is upper case in a few ways. Let’s take a look at some popular ones.


This is a built-in string method that returns the invoked string with only upper case characters:

function startsWithCapital(word){
    return word.charAt(0) === word.charAt(0).toUpperCase()

console.log(startsWithCapital("Hello")) // true
console.log(startsWithCapital("hello")) // false

Here, we’re making a single character string consisting of only the first letter/character of the provided string and comparing it to its upper case version. If they match, the original letter is uppercase.

Note: string.charAt(index) is preferred over string[index] (bracket notation). This is because "".charAt(0) returns an empty string whereas ""[0] returns undefined.


JavaScript: Check if First Letter of a String Is Upper Case
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