Usual answer is, “How much time and effort are you prepared to put in?”. There is no definitive answer to this, I am very dubious of any clubs who award black belts within 4 years as there is a level of maturity gained only from sustained training over a period of time. We pride ourselves on the standard of our members and will not compromise this just to have more black belts training under us. The grade is only a bi-product of training hard and improvement.
The above shows a reasonable journey through the belts, in comparison to a standard Shotokan group. It should be remembered that everyone is treated as an individual in our group and some will progress faster than the times shown below, while many take longer. Progression is all that matters, and that does not necessarily mean progression through the set syllabus.