How long will it be.

Thank you Zowee! Good answer. It was a quastion. And now I know that "How long will it be?" is right variant.

If it's a question, then 'How long will it be' [before you graduate?] If it's in a sentence then you could say 'I don't know how long it will be before I graduate'.....so it depends on the context, but as Andrew says, it is most likely you are asking a question and therefore it would be 'How long will it be...?' You might want to write a complete question as it also could be 'How long is it?' etc thanks! :)