BJJ Ranking System
Consistency is the name of the game in Brazilian Jiu Jitsu - the more often you train, the faster you will progress!
While everyone looks forward to it, receiving a belt won't make you any better at Jiu Jitsu. The belt is simply there to keep your jacket closed, but the skills and knowledge you gain on the journey will last a lifetime.

Belts
Like most martial arts, Brazilian Jiu Jitsu utilizes colored belts to recognize growth, achievement, and skill level.
Your instructor is responsible for deciding when and if you are ready to move up. Rank and promotion is primarily based on knowledge, ability, and time.
The IBJJF (International Brazilian Jiu Jitsu Federation) has strict rules about how quickly you may progress, age minimums for belt level, and the credentials of the instructor giving out the promotion.
Brazilian Jiu Jitsu has a highly rigorous rank system, with the path to black belt typically taking 10 or more years.

Stripes
Since it can take several years to earn your next belt, stripes are a method of tracking your progress. They also serve as a motivation and reward for improvement.
You can receive up to 4 stripes on your belt. A stripe is simply a white piece of tape that is wrapped around the black tab at the end of your belt.
Stripes are less formal than belts. Some BJJ instructors don't use stripes at all, and even at schools that do use stripes, an instructor can choose to promote someone to the next belt level prior to receiving all 4 possible stripes.

Adult Ranking
Adult belt ranks proceed in the following order:
WHITE
BLUE
PURPLE
BROWN
BLACK
The average time from white belt to black belt is 10-15 years. Brazilian Jiu Jitsu is a martial art that you can spend a lifetime learning, so don't worry about how long it takes to get your next belt.
IBJJF requirements for adult promotions:
Blue (16 years old), Brown (18 years old), Black (19 years old).

Kids Ranking
Kids will receive promotions within the junior ranking system until they reach the age of 16, at which time they will be eligible for an adult blue belt.
Besides the white belt, each color of belt has 3 ranks in the junior system. This allows kids to receive regular promotions to recognize their achievements, even when starting at a young age.
Kids belt ranks proceed in the following order:
WHITE
GREY WHITE > GREY SOLID > GREY BLACK
YELLOW WHITE > YELLOW SOLID > YELLOW BLACK
ORANGE WHITE > ORANGE SOLID > ORANGE BLACK
GREEN WHITE > GREEN SOLID > GREEN BLACK
IBJJF requirements for junior promotions:
Yellow (7 years old), Orange (10 years old), Green (13 years old)