Financial risk is the company's risk associated with the outlay that should be paid out by the project in order for the project to operate. To minimize financial risk, cost estimation is required. Cost estimates are used to find out how much it will cost to build the project. At the cost estimation stage, it often doesn't involve uncertainty and risk factors, whereas risk and uncertainty are important factors that are unavoidable in project costs. To measure the consequences of the risks and uncertainties of project financing, a Monte Carlo simulation is used to model and analyze the system to get the best project cost estimate. This study was conducted to determine the maximum and minimum value of the project based on the unit price of materials and wages, to know the probability of project success as per cost in Project's Cost Budget Plan to the cost estimation result, and to find out the percentage of cost comparison that will be experienced by the project from Monte Carlo simulation method with Microsoft Excel and Crystal Ball Software. In this research, analysis is done on the minimum unit price, the maximum unit price obtained from the interview result and the most likely unit price taken from the cost budget plan. The Monte Carlo simulation is done using Microsoft Excel and Crystal Ball software. So the simulation will result in a more realistic probability distribution of estimated cost values. From the research results obtained a minimum value of Rp 68,133,682,809.47, the maximum value of Rp. 106,485,596,066,01 and the contract value of Project's Cost Budget Plan worth Rp. 96,805,087,332.74. The probability percentage of successful project implementation as per cost in cost budget plan is 100%. Projects can earn profit of 9,82 % by using the results of analysis from Microsoft Excel, and earn profit of 6,42 % by using Crystal Ball analysis results.