The following links take you to the recognised grading system and weight brackets as laid down by the International Brazilian Jiu Jitsu Federation (ibjjf) and are used in the majority of BJJ competitions
BELTS - http://www.ibjjf.org/graduation.htm
WEIGHT GROUPS -
With Gi:
http://www.ibjjf.org/TABELA-PESO-OFICIAL-3-ingles.pdf
No Gi:
http://www.ibjjf.org/nogiweightlist.pdf