Will creating plugin increase memory more than if put code in functions.php?

No, not really. There may be a few bytes here and there, but the code is the code.

Using a plugin will add some files to your filesystem, a hundred or so bytes to the database, and potentially some bytes to memory usage. However, if you created a child theme for the sole purpose of adding code to functions.php, then using a plugin will reduce the filesystem, database, and memory usage because the child theme can be deleted.

The biggest difference is that the plugin’s code will be available to all themes, not just the one that previously contained the code.

Plugin code starts executing before theme code, which could be a plus or a minus depending on your code.

@sterndata thanks for the info

@diondesigns thank you. I’m creating a meta box in the editor to pick an option from a list of options, and I was planning to add the code in a plugin. In your opinion should I just add the code to the functions.php or it’s better to add a plugin. I use only one theme that I created and maintain.

• This reply was modified 2 years, 1 month ago by wpmhweb.

If the code you’re describing is specific to the theme, and you’re not creating a child theme solely for this code, then put the code in the theme’s functions.php. Otherwise, it probably makes more sense to create a plugin.