First a definition: A story point is a measure of the effort required to build out a story. It has nothing to do with time. Points usually occur on a 1-to-5 scale (where 1 represents a trivial effort), but some prefer a Fibonacci sequence (1, 2, 3, 5, 8, 13, 21…) because the further you get from trivial, the more the effort ratchets up. I can't emphasize too strongly that this measure has nothing to do with time beyond the broad observation that hard stuff takes longer. There is no way to map a point to a particular time interval.