How to Count Characters in a String in PHP

To count characters in a string in PHP, use the strlen() function which returns the length of the string including spaces and special characters. For multibyte strings (like UTF-8), use mb_strlen() to get the correct character count.

Syntax

The basic syntax to count characters in a string is:

• strlen(string $string): int - Returns the number of bytes in the string.
• mb_strlen(string $string, string $encoding = null): int - Returns the number of characters in a multibyte string, considering encoding.

Note: strlen() counts bytes, so it may not work correctly for multibyte characters like emojis or accented letters.

php

strlen(string $string): int
mb_strlen(string $string, string $encoding = null): int

Example

This example shows how to count characters in a simple ASCII string and a UTF-8 string with multibyte characters using strlen() and mb_strlen().

php

<?php
// ASCII string
$asciiString = "Hello World!";
echo "Length with strlen: " . strlen($asciiString) . "\n";
// UTF-8 string with multibyte characters
$utf8String = "Café 😊";
echo "Length with strlen: " . strlen($utf8String) . "\n"; // counts bytes
// Use mb_strlen to count characters correctly
echo "Length with mb_strlen: " . mb_strlen($utf8String, 'UTF-8') . "\n";
?>

Output

Length with strlen: 12
Length with strlen: 10
Length with mb_strlen: 6

Common Pitfalls

A common mistake is using strlen() for strings with multibyte characters like emojis or accented letters. strlen() counts bytes, not characters, so it can give a larger number than expected.

Always use mb_strlen() with the correct encoding (usually 'UTF-8') for multibyte strings.

php

<?php
// Wrong way: using strlen on multibyte string
$str = "😊";
echo strlen($str) . "\n"; // Outputs 4 (bytes), not 1 (character)

// Right way: using mb_strlen
echo mb_strlen($str, 'UTF-8') . "\n"; // Outputs 1 (character)
?>

Output

4
1

Quick Reference

Function	Purpose	Notes
strlen(string $string)	Counts bytes in string	Use for ASCII or single-byte strings
mb_strlen(string $string, string $encoding)	Counts characters in multibyte strings	Use 'UTF-8' encoding for most cases
mb_internal_encoding()	Gets or sets internal encoding	Useful to set default encoding for mb functions

Key Takeaways

Use strlen() to count characters in simple ASCII strings.

Use mb_strlen() with 'UTF-8' encoding for strings with multibyte characters.

strlen() counts bytes, which can be different from character count in multibyte strings.

Always specify encoding in mb_strlen() to get accurate results.

For most modern applications, prefer mb_strlen() to handle international text correctly.