Understanding PHP Post Max Size

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The post_max_size directive in PHP sets the maximum size for POST data that PHP will accept. This includes all form data submitted via the POST method. The default value for post_max_size is typically 8MB, but you can adjust it based on your application’s needs.

Common Use Cases

Increasing post_max_size is essential when your application needs to handle large form submissions. This is common in:

  • File uploads
  • Large data forms
  • Multimedia submissions

How to Configure post_max_size

To configure post_max_size, you need to edit the php.ini file. Here’s how you can do it:

  1. Locate php.ini: This file is usually found in your PHP installation directory. If you’re unsure of its location, you can create a PHP file with the phpinfo() function to find the path.
  2. Edit php.ini: Open the file in a text editor.
  3. Set post_max_size: Find the line that contains post_max_size and update its value. For example:
   post_max_size = 16M

This sets the limit to 16MB.

  1. Restart the Web Server: After making changes, restart your web server to apply the new settings.


If you encounter issues with POST data being truncated or not accepted, ensure that:

  1. The post_max_size value in php.ini is adequately set.
  2. The upload_max_filesize directive is less than or equal to post_max_size.
  3. The web server config does not have its own limits.

Interaction with Other WordPress and PHP Settings

WP Memory Limit and WP Max Memory Limit

WP_MEMORY_LIMIT and WP_MAX_MEMORY_LIMIT are constants in WordPress that define the maximum amount of memory WordPress can use.

  1. WP_MEMORY_LIMIT: This is the default memory limit for WordPress. It affects both front-end and back-end operations.
  1. WP_MAX_MEMORY_LIMIT: This is the memory limit for administrative tasks. It typically has a higher value.

These settings do not directly affect post_max_size, but they ensure that WordPress has enough memory to handle large POST requests.

PHP Max Execution Time

max_execution_time sets the maximum time in seconds that a PHP script is allowed to run before being terminated by the parser. The default is usually 30 seconds.

While max_execution_time does not directly interact with post_max_size, it plays a crucial role in handling large uploads or data submissions. If the execution time is too low, large POST requests might fail.


  • post_max_size: Controls the maximum size of POST data.
  • WP_MEMORY_LIMIT and WP_MAX_MEMORY_LIMIT: Ensure WordPress has sufficient memory to process POST data.
  • max_execution_time: Ensures scripts have enough time to process large POST requests.

By understanding and configuring these directives, you can optimize your WordPress site to handle larger data submissions effectively.