Demand of natural gas is always higher than the supply in Bangladesh. Currently there are 27 natural gas field in Bangladesh. Begumganj is one of the gas fields of Bangladesh Petroleum Exploration & Production Company Limited (BAPEX) which was discovered by BAPEX in 1977. Correct estimation of reserve is important for the development of the gas fields, design of production facilities and preparation of the gas contracts. The objective of this study is to estimate the Gas in Place (GIP), remaining reserve and production prediction of Begumganj gas field for which material balance method and decline curve analysis method have been used. Integrated Production Modelling (MBAL 10.5) software package developed by Petroleum Experts is used as a material balance and decline curve analysis tool for this project. Four years of production data (2015-2018) have been analyzed and found that gas in place in material balance is 100000 MMscf and in decline curve analysis is 110000 MMscf. Decline curve analysis shows 10% more value than material balance. For the production prediction material balance shows a limit upto 2033 while the decline curve shows a limit upto 2036. The main source of energy in reservoir was from water influx and rock and fluid expansion drive mechanism from which fluid expansion provide about 90% of the reservoir energy which is required for gas recovery. To find the amount of gas in place and production prediction various input data such as temperature, initial pressure, porosity, connate water saturation, water compressibility, initial gas cap, gas injection, water injection, gas lift injection, gas recycling, water recycling are required. This project is a representation of a few results obtained from real time data of gas reservoirs. With these results, it is assessed that Integrated Production Modelling (MBAL) software with its easy user interface is an optimum solution for estimating oil and gas reserves.