Google Translate can perform translations from single words to long paragraphs in many language pairs (e.g. English <-> German, English <-> Japanese). One can not expect great results, but the free service is constantly being improved and provides results that may be used to understand foreign texts. For this purpose Google Translate can be of great help.
In addition you can select a term in the source and you will get instantly a definition for the term, examples, and other useful information. And if you click on a term in the target field you get more suggestions for translations.
However, a note of caution should not be missing here: Since Google Translate is an online service, confidential texts should perhaps better not be translated with Google Translate.
In addition to this online service Google provides another translation tool called Google Translator Toolkit which is more complex and offers a lot of features modern CAT tools provide.