Increase WordPress limits and upload sizes on Ubuntu with Apache

Introduction

If your WordPress site fails during plugin installs, media uploads, imports, or bulk updates, you are often hitting resource ceilings rather than a WordPress bug.

This tutorial shows how to increase the most common limits on an Ubuntu server running Apache:

WordPress memory constants (WP_MEMORY_LIMIT, WP_MAX_MEMORY_LIMIT)
PHP memory_limit
PHP upload_max_filesize
PHP post_max_size

For background on how WordPress relates to these PHP directives, see the WordPress Developer Handbook page "PHP Optimization".

Prerequisites

A server running Ubuntu with SSH access (for example, a Hetzner cloud server)
A working WordPress installation
Admin access to the server (root or a sudo-capable user)
A text editor available on the server (nano or vim)

Example terminology

This tutorial uses placeholders like:

Username: holu
IP address: YOUR_SERVER_IP
Domain: YOUR_DOMAIN
WordPress root: /var/www/html

Replace them with your own values.

Step 1 - Connect via SSH and locate your WordPress root

SSH to the server:

ssh holu@YOUR_SERVER_IP

A common WordPress root on Apache installs is:

cd /var/www/html
ls -la

You should see wp-config.php and directories such as wp-content/, wp-admin/, and wp-includes/.

If you do not see wp-config.php, search for it:

sudo find /var/www -type f -name wp-config.php 2>/dev/null

Then cd into the directory that contains it.

holu@example:~$ cd /var/www/html
holu@example:/var/www/html$ ls -la
total 248
drwxr-xr-x  5 www-data www-data   4096 Dec 29 10:01 .
drwxr-xr-x  3 www-data www-data   4096 Dec 28 16:25 ..
-rw-r--r--  1 www-data www-data    704 Dec 29 10:00 .htaccess
-rw-r--r--  1 www-data www-data    405 Feb 6   2020 index.php
-rw-r--r--  1 www-data www-data  19903 Dec 28 16:38 license.txt
-rw-r--r--  1 www-data www-data   7425 Dec 28 16:38 readme.html
drwxr-xr-x  9 www-data www-data   4096 Nov 21  2024 wp-admin
-rw-r--r--  1 www-data www-data    351 Feb 6   2020 wp-blog-header.php
-rw-r--r--  1 www-data www-data   3323 Jun 14  2023 wp-comments-post.php
-rw-r--r--  1 www-data www-data   3652 Dec 29 09:58 wp-config.php
-rw-r--r--  1 www-data www-data   3339 Dec 28 16:38 wp-config-sample.php
drwxr-xr-x  7 www-data www-data   4096 Dec 28 16:38 wp-content
drwxr-xr-x 31 www-data www-data  12288 Dec 28 16:38 wp-includes
-rw-r--r--  1 www-data www-data   2493 Dec 28 16:38 wp-links-opml.php
-rw-r--r--  1 www-data www-data   3937 Mar 11  2024 wp-load.php
-rw-r--r--  1 www-data www-data  51437 Dec 28 16:38 wp-login.php
-rw-r--r--  1 www-data www-data   8727 Dec 28 16:38 wp-mail.php
-rw-r--r--  1 www-data www-data  31055 Dec 28 16:38 wp-settings.php
-rw-r--r--  1 www-data www-data  34516 Dec 28 16:38 wp-signup.php
-rw-r--r--  1 www-data www-data   5214 Dec 28 16:38 wp-trackback.php
-rw-r--r--  1 www-data www-data   3205 Dec 28 16:38 xmlrpc.php
holu@example:/var/www/html$

Step 2 - Back up configuration files

From the WordPress root directory, back up wp-config.php:

sudo cp -a wp-config.php wp-config.php.bak.$(date +%F)

Back up .htaccess if it exists:

test -f .htaccess && sudo cp -a .htaccess .htaccess.bak.$(date +%F)

Step 3 - Increase WordPress memory limits in wp-config.php

WordPress has its own memory configuration constants that you can set in wp-config.php. The WordPress Developer Handbook documents these constants and explains how they interact with PHP's memory_limit.

Edit wp-config.php:

sudo nano wp-config.php
# or: sudo vim wp-config.php

Add the following lines above the line that says "That's all, stop editing":

define('WP_MEMORY_LIMIT', '256M');
define('WP_MAX_MEMORY_LIMIT', '512M');

Save and exit.

Notes:

WP_MEMORY_LIMIT applies to frontend rendering.
WP_MAX_MEMORY_LIMIT applies to admin and logged-in contexts, and is commonly relevant for media operations.
WordPress cannot exceed the PHP memory limit if PHP is capped lower than these values.

Step 4 - Check how PHP is connected to Apache

Whether you can set PHP directives in .htaccess depends on how PHP runs behind Apache.

Run:

apache2ctl -M | grep -E 'php|proxy_fcgi|mpm'

Interpretation:

If you see php_module, Apache is using mod_php and .htaccess directives like php_value typically work.
If you see proxy_fcgi_module, the site is often using PHP-FPM, and php_value in .htaccess may cause a 500 error.

Step 5 - Increase PHP limits (recommended approach for mod_php)

The WordPress Cloud App image from Hetzner installs Apache2 and WordPress along with PHP extensions.

Option A - Use .htaccess (recommended when apache2ctl shows php_module)

If Step 4 shows php_module, add PHP limits to the WordPress .htaccess file.

Edit .htaccess in the WordPress root:

sudo nano .htaccess
# or: sudo vim .htaccess

Add this block near the top (or near the existing WordPress section):

# BEGIN WordPress PHP limits (mod_php)
php_value memory_limit 256M
php_value upload_max_filesize 64M
php_value post_max_size 64M
php_value max_execution_time 300
php_value max_input_time 300
# END WordPress PHP limits (mod_php)

The WordPress Developer Handbook notes that upload sizes are controlled by PHP upload_max_filesize and post_max_size, and that post_max_size must be greater than or equal to upload_max_filesize.

Option B - If .htaccess is not supported (PHP-FPM), use .user.ini

If adding php_value triggers a 500 error, you are likely not running mod_php. In that case, use .user.ini instead.

Create or edit .user.ini in your WordPress root:

sudo nano .user.ini

Add:

memory_limit=256M
upload_max_filesize=64M
post_max_size=64M
max_execution_time=300
max_input_time=300

Save and exit.

Step 6 - Restart services and verify the new limits

Restart Apache:

sudo systemctl restart apache2

If you are using PHP-FPM, restart it too (replace VERSION):

sudo systemctl restart phpVERSION-fpm

Examples:

sudo systemctl restart php8.2-fpm
sudo systemctl restart php8.3-fpm

Verify in WordPress Site Health

In WordPress admin at YOUR_DOMAIN/wp-admin, go to Tools -> Site Health
Open the Info tab
Check values such as memory limits and maximum upload size

https://YOUR_DOMAIN/wp-admin/site-health.php

Verify with phpinfo (temporary)

Create a temporary file:

echo "<?php phpinfo();" | sudo tee /var/www/html/phpinfo.php >/dev/null

Open http://YOUR_DOMAIN/phpinfo.php and verify:

memory_limit
upload_max_filesize
post_max_size

Then remove the file immediately:

sudo rm -f /var/www/html/phpinfo.php

Step 7 - Troubleshooting and rollback

500 Internal Server Error after editing .htaccess

Likely causes:

The server uses PHP-FPM (FastCGI), so php_value directives are not allowed in .htaccess.
A directive was mistyped.
.htaccess overrides are disabled.

Fix:

Restore your .htaccess backup (if you made one in Step 2):
```
sudo cp -a .htaccess.bak.$(date +%F) .htaccess
```
If you do not have a backup, remove only the block you added.
Restart Apache:
```
sudo systemctl restart apache2
```
Use Step 5 Option B (.user.ini) or set the values in php.ini / PHP-FPM pool configuration.

Upload size does not increase

Double-check these points:

post_max_size is greater than or equal to upload_max_filesize.
A reverse proxy, WAF, or CDN is not enforcing its own request size limits.
WordPress is not constrained by an application-level restriction in a plugin.

Conclusion

You have now:

Increased WordPress memory limits via wp-config.php
Increased PHP memory and upload limits using the approach that matches your PHP runtime
Verified the result and captured rollback steps