Should You Add Code in Functions.php or Use a Plugin?

Should You Add Code in Functions.php or Use a Plugin?

John Hewick

Should you use functions.php file? Or WordPress plugin? That is the big question! While some favour code as they feel it always ensures a better performance, others disagree. Here in this article, we will be taking you through the pros and cons of each of these so you can make an informed decision on which method you think is better.

What’s the Difference?

There are two ways in which you can add something to your WordPress website. Both methods do exactly the same thing and there is no right or wrong answer, however, there are pros and cons to both and many people prefer one to the other and think it is better for overall speed and performance.

The Positives and Negatives of Functions.php File

With the functions file in WordPress, as a theme developer you can define the custom functionality of it. Essentially, this is a giant WordPress plugin and you can use it to add custom code snipes for your website. Below you can find some of the positives of using custom code on your theme’s function.php file.


  • It’s easy to use as there is a built-in theme editor in the admin area where you can change the functions.php file.
  • All of the code can be copied and pasted in one file.
  • You can learn how the coding actually works.

Here, you can find some of the disadvantages to using functions.php file.


  • If you switch themes, the custom code won’t work.
  • When you update your theme, the functions.php file will be overwritten
  • It can become confusing to see where the theme code ends and the custom code begins
  • You may need to use additional scripts and styles if the code snippets are too big

The Positives and Negatives of Installing WordPress Plugins

If you are not familiar with what a WordPress plugin is, it is essentially like an app but for your website. These plugins contain code that provides your website with added features and functionality, making it more user-friendly and better for people to use. There are lots of advantages to using a WordPress plugin.


  • They don’t depend on your theme
  • If the code is the same, then it has the same performance impact as changing the code
  • You can easily disable, reinstall or update it when you need to
  • They are easy to manage as the description will tell you what each plugin does

However, there are a few disadvantages to using WordPress plugins.

  • Updates have to be installed for plugins
  • If it’s a free plugin, the author may abandon it in the future
  • You don’t get a better understanding of the actual code

Which Is Better?

It really depends! If the plugin uses the same code, then this is definitely a better option. Whether this code runs from one or the other really doesn’t matter in terms of performance. It is also easier to manage different plugins and you can benefit from future updates.

John Hewick

Author John Hewick

John is a full stack developer, with 10 years’ experience building websites with WordPress. Working with Elementary Digital for the last 4 years John has met all the challenges that have been sent his way.

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