What is the difference between a hypothetical imperative and a categorical imperative?

The hypothetical imperative is a test used to determine whether or not you will do an action. You must imagine a world in which everyone does the proposed action. If it is not possible the action should not be performed. For example, if everyone didn't speak until they were spoken to, no one would ever speak, so this idea would not get thorugh the first test.

However, if you can imagine a world in which everyone did certain action then this action must go though a second test. This is the categorical imperative. If everyone did the propoesed action would you like that? For example. If you can imagine a world in which everyone spat out their gum on the sidewalk this would go through the hypothetical imperative but you wouldn't want to live in this world so it wouldn't go through the categorical imperative.

Hope i helped :)