By Kezz Bracey, Tuts Plus
The quickest way to answer the question “What is a WordPress child theme?” is with this summary:
“A WordPress child theme is a sandbox in which you can safely customize the look of your site without losing your changes later during upgrades.”
In our article “What is a WordPress Theme?” we described how a theme is like a set of clothes for your WordPress site, controlling everything about how it looks.
So then, what is a child theme in WordPress, in the context of this same analogy?
Another Clothing Analogy
Imagine you just bought a jacket you really like, but there are a couple of customizations you want to make. So you dye it a different color, sew a patch onto the arm, and add in some pockets. It takes a good number of hours but now everything is just how you want it.
Then a while later the designers of the jacket release a new version in the same line. You really want to upgrade to it but if you do you’ll either lose all your modifications or have to do each one again from scratch. You wish there was a way you could just upgrade to the new version of the jacket and carry over your modifications automatically.
Unfortunately, a feat such as this isn’t possible in the world of clothing.
However, in WordPress, it’s absolutely possible, through the use of child themes.
What is a WordPress Child Theme? It’s Safe Customization
In WordPress, any theme can be “extended”, which is effectively another way to say customized, through a child theme. Once a child theme is in place the original theme becomes known as the “parent”.
The child theme can then be used to modify anything about the parent theme, such as color, layout, typography, and more. But if the parent theme later gets an update from its developer it can be freely applied without causing you to lose any of the modifications, because they are all safely contained within the child theme.
Without a child theme, any customizations made to the original theme’s files would simply be overwritten when the newer versions were downloaded during updates.
In our earlier analogy, if the parent theme were the jacket, the child theme would be a kit containing the different colored dye, the patch, and the pockets. The key difference is this kit would have the magical ability to automatically apply itself to any newly released version of the original jacket.
What is a Child Theme’s Greatest Value?
Some theme developers leverage the WordPress child theme system to great effect by providing a parent theme that focuses on excellent functionality while offering several child themes, each of which focuses on creating a different look.
This enables them to frequently offer functionality upgrades via the parent theme, knowing the appearance of their customers’ sites is protected inside separate child themes. For a developer, this means the freedom to evolve their projects more rapidly, and happier customers who get both new features and stability at the same time.
And for a person managing their own site, what a child theme in WordPress means is a safe place to make customizations that won’t be lost later during parent theme upgrades.
So if you see the almost perfect theme but just want to change a few things, or you like to tinker and turn designs into something of your own, remember what a child theme in WordPress can do to help you along your way.
