First, you should know that the full form of CTC is Cost To Company, which means any cost related to employees is included in the company's CTC. Gratuity is also one type of expense for the employer, given after completing five years of work. Only then are you eligible for it; otherwise, not. Each year, the company includes this expense in its balance sheet as an advance Gratuity provision for all employees. If you have not completed the required five years, then this does not count as a cost to the company. However, if you have completed the required time, you are eligible for Gratuity.
Regards,
Vivek