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Raising the WordPress Upload Limit Means Finding Which of Four Limits You Hit

wordpress php sysadmin

"The uploaded file exceeds the upload_max_filesize directive in php.ini." Every WordPress administrator meets this message the first time someone tries to upload a video. The fix is a one-line setting. The trouble is that there are four places the setting can live, they override each other, and WordPress adds a fifth limit of its own on multisite installations. Here is how to find out which one is stopping you and how to change it.

First, See What You Have

Do not guess. Put a file called info.php in the web root with one line in it:

<?php phpinfo();

Open it in a browser and search the page for upload_max_filesize. The table shows two columns, local value and master value. The master value is what the system php.ini says; the local value is what applies to this directory after every override. Note also post_max_size, memory_limit, and max_execution_time, because an upload has to fit through all of them:

  • upload_max_filesize is the size of one uploaded file.
  • post_max_size is the size of the whole request, so it must be at least as large as the file, and a little more.
  • memory_limit should be larger than post_max_size, or PHP runs out of memory handling the request.
  • max_execution_time and max_input_time decide whether a slow upload is cut off before it finishes.

Delete info.php when you are done. It tells the world your exact PHP configuration, and there is no reason to publish that.

Option One: The System php.ini

If you own the server, the honest fix is the system file. On Debian and Ubuntu with Apache it is /etc/php5/apache2/php.ini; the phpinfo page names the exact path under "Loaded Configuration File". Change these lines:

upload_max_filesize = 64M
post_max_size = 72M
memory_limit = 128M
max_execution_time = 300
max_input_time = 300

and restart the web server:

sudo /etc/init.d/apache2 restart

This applies to every site on the machine, which is either exactly what you want or exactly what you do not.

Option Two: A Local php.ini

On shared hosting you cannot touch the system file, but many hosts run PHP as CGI or FastCGI, and then PHP reads a php.ini from the directory of the script being run. Put a file with just the changed lines in the WordPress root:

upload_max_filesize = 64M
post_max_size = 72M
memory_limit = 128M

Two traps. First, the file applies to the directory it is in, not to subdirectories; the upload is actually handled by wp-admin/async-upload.php, so you may need a copy in wp-admin/ too. Second, on some hosts the file must be called php5.ini or .user.ini. The phpinfo page tells you whether your change took: if the local value did not move, PHP is not reading your file.

Option Three: .htaccess

If PHP runs as an Apache module rather than CGI, a local php.ini is ignored and the equivalent is Apache directives in .htaccess:

php_value upload_max_filesize 64M
php_value post_max_size 72M
php_value memory_limit 128M
php_value max_execution_time 300
php_value max_input_time 300

If PHP is not running as a module, these lines cause a 500 error on the whole site, because Apache does not know the php_value directive. That is the quick way to find out which mode you are in: try it, and if the site dies, remove the lines and use option two. Only one of options two and three will work on a given host, never both.

Option Four: WordPress Multisite

You have raised every PHP limit, phpinfo confirms it, and uploads still fail at a smaller size. Then you are running multisite, and the network has its own ceiling. It lives in the network admin under Settings, as "Max upload file size", in kilobytes, with a default of 1500. It also lists the allowed file types, which is why a .mkv may be refused even when its size is fine. Raise both there. There is additionally a per-site space quota on the same page, which counts total uploads rather than a single file, and it stops uploads with a different and less helpful message when a site fills up.

The Order to Try

Check phpinfo first, so you know whether the limit is PHP's or WordPress's. If it is PHP's, use the system file when you can, a local php.ini when PHP is CGI, and .htaccess when it is a module. If the PHP limits are already large enough, the answer is on the network settings page. Doing them in this order takes ten minutes; doing them in a random order is how people spend an afternoon on a one-line change.