| Naeem, Tat is right and if you have to calculate overtime it is better to find the hourly rate : Total Salary per month *12/365/8hrs. For gratuity also you can find the rate per day and then pay as per the UAE LABOR LAW.
GRATUITY (As per Article 137)
UNLIMITED CONTRACTS:
For an employee who is employed and has a contract for an unlimited term. If this employee resigns after completing 1 year of continuous service of no less than at least 1 full year and not more than 3 years. In this case he is entitled to 1/3 of ESB. If this same period of continuous employment was more than 3 years but not more than 5 years, then he would be entitled to 2/3 of ESB. IF HIS CONTINUOUS SERVICE IS MORE THAN 5 YEARS, HE WOULD BE ENTITLED TO FULL GRATUITY.
WHAT IS FULL GRATUITY:-
For Termination / Redundancy: –
a) 21 days of salary for each year of the first 5 years
b) 30 days for each additional year after the first 5 years on the stipulation that the total of the gratuity does not exceed the salary of 2 years.
For Resignation: –
a) 7 days of salary for each year for the first, second, and third year if total employment was more than 1 year but less than 3 full years.
b) 14 days of salary for each year for the first, second, third, and forth year if total employment for more than 3 years but less than 5 full years.
c) On the successful completion of the fifth year, it will be 21 days for all five years.
d) More than 5 years. It will be 30 days for each additional year after the first 5 years on the condition that the total of the gratuity does not exceed the salary of 2 years.
LIMITED CONTRACTS:
A) Article 138
Where a worker under a definite term contract abandons his employment at his own
initiative before the expiry of his contract period, he shall not be entitled to severance pay unless his continuous period of service exceeds five years. (If an employee who is employed under a contract for a limited period on the other hand chooses to resign before the end of the contract, he is not entitled to end of service gratuity unless his continuous service exceeds five years).  | 
