Are you talking to one person? If so, use "Du".* Are you speaking to two or more people, use "ihr".

*If you are talking with someone and he says that he and his family are going somewhere and you want to ask where they are going, you can use word "ihr" as in "Wohin geht ihr?" even though you are only speaking directly to him- or as we would say in my part of the US "Where are you guys going?" The person responding would most likely answer using the word "wir" as in "Wir fahren nach Berlin" - in English, "We are going to Berlin". So you could use "ihr" with one person, but you would be referring to a group.

Du means "you" (or "thou" in Victorian English and earlier), a single person you speak to. Ihr means "you (all)". Ihr can also mean "hers" but that's easier to distinguish.

'du' - second person SINGULAR - translated as 'you' "ihr' - second person PLURAL - translated as 'you' Notice that the actual verb endings are different in each case.

Thank you all for your answers, I appreciate it!

Du = One Person

Ihr = More than one Person