How tall can a snake stand up?

While I am certain the longer a snake is, the taller it can get when it "stands up", I am not exactly sure how much of the snake body length can "stand up" and become the height.

Lets say if a snake is 5 feet long. How tall can it be when it stands up?
Is it a fixed percentage of its length (always the same height) or can a snake stand up taller and shorter as it want?