How long in Karate does it take to be promoted a level?

Answer 1

3 months

That depends entirely upon the school and organization. In some the time increases as you progress up the ranks, taking a year from 1st kyu to black belt. I have no specific time frame for promoting students, it is based entirely on their ability and dedication. Someone that works hard and shows up to every class is going to move faster than someone that doesn't show up very often.