PHP get file extensions (with code example)

You need to call the pathinfo() function to get the file extension in PHP.

Here’s an example:

$file = "Picture.png";

$ext = pathinfo($file, PATHINFO_EXTENSION);

echo "The file extension is $ext";

The output will be:

The file extension is png

Explanation

The pathinfo() is a built-in PHP function used to get information from a file path.

pathinfo(
    string $file,
    int $flags = PATHINFO_ALL
): array|string

The function returns either an array or a string depending on the parameter you passed into it.

The two parameters are:

1. The $file string that you want to parse
2. The $flags to specify what you want to get from the $file

There are four valid $flags values:

• PATHINFO_DIRNAME
• PATHINFO_BASENAME
• PATHINFO_EXTENSION
• PATHINFO_FILENAME

If you don’t pass a $flags value, then PHP will get all four information as an array of strings.

This is why to get a file extension, you pass the string of the file path and the PATHINFO_EXTENSION to the function:

$ext = pathinfo($file, PATHINFO_EXTENSION);

When you upload a file using an HTML <input> tag, you need to get the file name parameter from the $_FILES array.

Here’s an example code to get the extension from an HTML form:

<?php
if ($_SERVER["REQUEST_METHOD"] == "POST") {
    $file = $_FILES["the_file"];
    $filename = $file["name"];

    $ext = pathinfo($filename, PATHINFO_EXTENSION);
    echo "<h1 style='color:red;'>The file extension is $ext</h1>";
  }
?>

<h1>PHP Get file extension</h1>
<form 
   method="post" 
   action="" 
   enctype="multipart/form-data">
    File:
    <input type="file" name="the_file">
    <input type="submit" name="submit" value="Submit">
</form>

When you put a file into the <input> type and hit submit, the file extension will be printed on the page.

Here’s an example of the PHP code in action:

And now you’ve learned how to get the file extension in PHP. Nice work! 👍