I recently received a support ticket from someone who wished to exclude specific categories from the default WordPress category widget without using a plugin. In this tutorial, I will show you How to exclude categories from the WordPress category widget without a plugin
Exclude categories from the WordPress category widget - Step One:
The first thing we will need to do is determine the category ID. You can install a plugin which will reveal all IDs (and then delete the plugin after you've identified the ID). Or, you can do it without a plugin. Go to Dashboard > Categories > All Categories > hover over the edit button of the category you wish to exclude; in your browser's admin bar, you will see a stream of text; make a note of the category ID:

Exclude categories from the WordPress category widget - Step Two:
Navigate to your functions.php file (Dashboard > Appearance > Editor > functions.php), and add this to the bottom of the file:
That will remove the category from the widget if you're not using the drop-down option.
Exclude categories from the WordPress category widget - Step Three
If you're using the drop-down option, you'll need to add additional code. Add this to your functions.php file (adjusting the code to reflect the category ID you wish to exclude - you can exclude multiple categories by adding your category ID, divided by a comma:
Here's a screenshot showing how it looks added to the functions.php file on my site.
Here's the "before" and "after":
Thanks for Davinder Singh of BasicWP for providing this code.
If you're using a theme built on the Genesis Framework, and are interested in having me implement this for you, send me a note!
Did you know I offer a theme setup service? Get your Genesis WordPress theme installed and set up like the demo in under 24 hours. Learn more here.
Sajid Blue says
I was trying to add multiple category ids by comma, but it show error. but it works for single category id.
Your PHP code changes were rolled back due to an error on line 193 of file wp-content/themes/pixwell/functions.php. Please fix and try saving again.
syntax error, unexpected ' ' (T_STRING)