The post_max_size is a crucial PHP configuration setting that controls the maximum size of POST data that PHP will accept. This includes all data submitted through forms, particularly important for file uploads on your hosting account.

When users upload files through your website forms, the post_max_size determines whether PHP will process the request or reject it entirely. This setting works in conjunction with upload_max_filesize, but with an important distinction:

• upload_max_filesize - Controls maximum size of individual files
• post_max_size - Controls total size of all POST data combined

For proper file upload functionality, you must set post_max_size to be larger than upload_max_filesize. A common configuration is:

• upload_max_filesize = 64M
• post_max_size = 65M

If post_max_size is exceeded, PHP will not process any of the POST data, and your form submission will appear empty. Users might see error messages or simply experience failed uploads without clear explanation.

To check your current settings, create a PHP file with phpinfo(); or contact your hosting provider. Remember that modifying these values typically requires access to your php.ini file or hosting control panel settings.

Proper configuration of post_max_size ensures your website can handle file uploads reliably, preventing frustrating user experiences and maintaining smooth operation of your online forms and applications.