This research describes techniques for estimating the boil-off gas generation rate from refrigerated vessels of liquefied natural gas plant. Appropriate thermodynamic, heat transfer due to heat-ingress in radiation, convection and conduction and displacement functional equations were utilized to bring the research to fruition. The BOG computing process was made possible by considering the heat leaks into loading and circulation pipelines, heat ingress from loading and circulation pumps and vapourized products from flashing refrigerated product. The aggregate results from these five points of BOG losses stood at 35,458.20 kg/hr and its cash equivalent loss at $16,636.88/hr @ $9 per MMBtu of LNG.