Can i get cost-benefit analysis for HRMIS ?

Ismail, the cost benefit analysis of applying an HRMS is different from company to company. Only you can determine what the automation of processes are worth to your organisation.

Anybody else's figures aren't much use to you.

I agree with Nik although their is basic data that you will need to determine the CBA. You must first have a clear understanding of the cost of what you are doing now with either another system or manually. The more detailed the cost analysis here the better you understand both your current process and what presents an opportunity to improve. You then need to understand the complete cost of the new application as well as be able to realistically project the efficiency savings it will present. Often times real savings are from time as opposed to anything else. However, I have established significant savings by automating transactional processes and eliminating the need for less skilled or clerical workers. The reduction in headcount amounts to a one time real savings.

Lastly when comparing the data you have gathered it is important to focus on how fast you can recover the initial cost. Obviously the faster the better.