Which is correct then or than?

However, the words then and than have very different meanings and uses in language. Then is used in several different ways relating to the element of time. It is most commonly used as an adverb and, in some specific cases, as an adjective and noun. You need to apologize, and then you can come back in.

What is the difference with then and than?

Remembering the differences:

Remember that then is usually associated with time and both words have the letter E in them. So, if you're talking about something related to time, use then. Than is usually associated with comparisons. Notice both words have the letter A in them.