From the colors of the belt, one can easily judge the rank and the level of expertise of any person doing Karate. The more common color that we come across is white and black. Where White represents the starting level, Black represents the true expert having the highest rank. A Black belt shows that the person wearing it has mastered all the skills and has a great ability to enlighten others with knowledge. Yellow, Orange, Red, Green, and Blue are other belt colors in Karate.

Source: Tutorials Point