PHP Memory Limit

memory_limit is the maximum RAM one PHP process may use. If a script uses more, PHP stops with an error such as Fatal error: Allowed memory size of 134217728 bytes exhausted. The number 134217728 bytes means 128 MB.

Where the setting is read

The effective value comes from the global php.ini, the PHP-FPM pool configuration, .user.ini or .htaccess depending on SAPI, then ini_set() in the app if allowed. Because of that, phpinfo() or php -i | grep memory_limit is more accurate than guessing from a hosting dashboard.

In cPanel, open MultiPHP INI Editor, select the domain, and change memory_limit. On a PHP-FPM server, set php_admin_value[memory_limit] in the relevant pool, then restart FPM. The CLI value can differ. Check with php -r 'echo ini_get("memory_limit");'.

When raising it makes sense

Large imports, migrations, image or PDF generation, and CLI tools such as Composer or WP-CLI sometimes need more memory. Raise it in steps, for example 128 MB to 256 MB to 512 MB, while measuring.

Do not jump to -1 or unlimited. One bad script can consume server RAM and affect other accounts.

When not to raise it

If the error appears on an ordinary page with little content, a higher limit only delays the problem. Find the cause: a plugin loading an entire table, an unbounded loop, a very large image, or a missing cache.

On shared hosting, the provider sets the ceiling. If your needs consistently exceed the plan, moving to a VPS or larger plan makes more sense than forcing the limit.

Common mistakes

Editing the wrong php.ini is a common mistake because a server can have several PHP versions. Forgetting to restart PHP-FPM leaves pool changes inactive. Raising the limit without monitoring RAM can affect other accounts.

A memory error does not always mean the limit is too small. It may be a leak or oversized data. See PHP and PHP-FPM for server context. If the error appears as Error 500, check the log before changing configuration.

FAQ