Key Difference: The terms ‘bye’ and ‘goodbye’ are quite similar. They are both parting phrases, which means that they are used when people part ways, i.e. are going their own way. ‘Goodbye’ seems to be too formal, while ‘bye’ is the shortened and less formal way of saying ‘goodbye’.

‘Goodbye’ seems to be too formal, while ‘bye’ is the shortened and less formal way of saying ‘goodbye’. The terms ‘bye’ and ‘goodbye’ are quite similar, which is why the confusion between what to use arises. Both, ‘bye’ and ‘goodbye’ are nouns that are commonly used as interjections.