Grade 1 Referees: Referees who officiate in the World Cup and international matches are designated as Grade 1.
Grade 2 Referees: Assistant Referees to Grade 1 Referees are designated as Grade 2.
Grade 3 and 4 Referees: In the United States, competition at the national level (including professional soccer and MLS) requires Grade 3 or 4. Grade 3 indicates the referee's readiness to be considered for international service.
Grade 5 and 6 Referees: The highest level of competition within a state (amateur leagues beyond youth) requires a Grade 5 or 6 where Grade 5 indicates the referee's readiness to be considered for national service.
Grade 7 Referees: Grade 7 is an experienced referee in the state qualified to officiate all but the highest levels of amateur soccer.
Grade 8 Referees: Most referees begin their careers as Grade 8 having taken the entry training course.
Grade 9 Referees: Very young aspirants to refereeing may take an abbreviated training course and be registered as Grade 9 which qualifies them only for very young "small sided" matches (usually seven and eight year old players in six per team matches)