[[Image:HotCat.png|thumb|right|400px|Example of HotCat usage]]
Whenever a page is loaded, HotCat looks for the category bar. If there are visible categories, it adds links to easily remove, change or add categories:
HotCat enwp Category bar.png|800px|A category bar as modified by HotCat]]
The new links are:
* "(-)" after a category: when clicked, the category is automatically
[[#Removing a category|removed ]].
* "(±)" after a category: when clicked, an input field to
[[#Changing a category|change this category ]] is opened.
+)" at the end of the list of categories: when clicked, an input field to [[#Adding a category|add a category]] is opened.
+<sup>+</sup>)" at the front: when clicked, enters [[#Making more than one category change|multi-change mode]], allowing modifying more than one category.