How to convert string to uppercase in PHP?

Use strtoupper($string). Example: strtoupper('hello') returns 'HELLO'.

How to capitalize only the first letter?

Use ucfirst($string) for first letter, or ucwords($string) for first letter of each word.

String Function PHP 4+

The strtoupper() function converts all alphabetic characters in a string to uppercase.

strtoupper(string $string): string

Parameter	Type	Description
`$string`	string	The input string

Returns the string with all alphabetic characters converted to uppercase.

Output

Click Run to execute your code

<?php
$title = "welcome to php";
echo strtoupper($title);
// "WELCOME TO PHP"
?>

<?php
$str = "hello world";
echo ucfirst($str);   // "Hello world"
echo ucwords($str);   // "Hello World"
?>

Note: For UTF-8 strings, use mb_strtoupper() instead.