How to Make a String Lowercase or Uppercase in PHP

Sometimes all characters in a string need to be changed from uppercase to lowercase and visa versa. Fortunately, PHP has built-in functions for changing the case of characters in both directions.


To Lowercase Using strtolower()

To convert a string to lower case in PHP use the strtolower() function. Pass the string to lowercase inside the () (parenthesis) - this can be a variable or the string itself.


strtolower("mIxEd CASE TeXt.");
mixed case text.


To Uppercase Using strtoupper()

To convert every character of a string to uppercase use the strtoupper() function. It accepts one parameter, the string/variable to uppercase.


strtoupper("mIxEd CASE TeXt.");



You now know how to change the case of every character in a string to uppercase or lowercase using PHP.

string character case