All I know is that both afterward and afterwards are used as an adverb which also mean "at a later time" or "later, then, following that or subsequent. Another thing is that, North American uses afterward, while those who are outside the North America uses afterwards.

The question already has an answer: The words afterward and afterwards are both used correctly. The only significant limitation is that when the word afterwards is used, it can only be used as an adverb and in relation to time. For example: "The boy needs to eat all of his dinner and he can have dessert afterwards." It is considered more formal to use the word afterward without the "s" at the end. Also if a person is describing