Well... theres 100mg in a point. (A point is 0.1 of a gram.. hence calling it a point)
But that doesn't mean that your going to get 100mg of Meth in your point even if it is pure...
Depending on how good/pure the Meth is, a point (for me anyway) is enough to keep me at least keep me up all night (worst case) or having me peaking off my head, talking fast, sweaty palms, dancing like a lunatic for the next 8 hours and not being able to sleep until WAayyyyy into the next night..
Hope that helped.