Generally, translators "translate" written texts, and interpreters "translate" spoken material. Thus, a person who works at the United Nations and does simultaneous "translation" of Chinese into English is an "interpreter," whereas someone who "translates" Harry Potter from English into French is a "translator."

In what context? In computer science they perform very differently. The translator generates output that can be post processed while an interpreter performs an operation without necessarily producing output requiring further operations.