PHP 8 reference · Multibyte String Functions

PHP mb_strtoupper() Function

Convert a string to uppercase, including letters outside ASCII such as é, ß and Cyrillic. The Unicode-aware strtoupper().

PHP 8 Since 4.3

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Syntax

mb_strtoupper(string $string, ?string $encoding = null): string

Parameter	Description
`string`	The input string.
`encoding` optional	The character encoding; defaults to `mb_internal_encoding()` (UTF-8).

The uppercased string.

Accented lettersTry it yourself

<?php
echo strtoupper("crème"), "\n";
echo mb_strtoupper("crème"), "\n";

Output

CRèME
CRÈME

Special casesTry it yourself

<?php
echo mb_strtoupper("straße"), "\n"; // ß becomes SS
echo mb_strtoupper("привет"), "\n";

Output

STRASSE
ПРИВЕТ

Version	Change
PHP 4.3	Added

strtoupper() · Convert every ASCII letter in a string to uppercase. Letters such as é stay unchanged; use mb_strtoupper() for those.
mb_strtolower() · Convert a string to lowercase, including letters outside ASCII such as É, Ü and Cyrillic. The Unicode-aware strtolower().
mb_convert_case() · Change the case of a string with Unicode rules: upper, lower, title case or case folding for comparisons.
PHP Strings · tutorial