I AM THAT I AM. No better translation can be given of the Hebrew words. "I will be that I will be (Geddes) is more literal, but less idiomatic, since the Hebrew was the simplest possible form of the verb substantive.
"I am because I am" (Boothroyd) is wrong, since the word asher is certainly the relative. The Septuagint, ἐγώ εἰμι ὁ ὤν, explains rather than translates, but is otherwise unobjectionable. The Vulgate, sum qui sum, has absolute exactness.
The idea expressed by the name is, as already explained, that of real, perfect, unconditioned, independent existence. I AM hath sent me to you. "I am" is an abbreviated form of "I am that I am," and is intended to express the same idea.