Methane emission from landfill gas emission (LandGEM) model was validated through the results of laboratory-scale biochemical methane potential assay. Results showed that the LandGEM model overestimates methane (CH4) emissions, and the true CH4 potential of waste depends on the level of segregation. Based on these findings, correction factors were developed to estimate CH4 emission using the LandGEM model, especially where the level of segregation is negligible or does not exist. The correction factors obtained from the study were 0.94, 0.13, and 0.74 for food waste, mixed un-segregated municipal solid waste (MSW), and vegetable wastes, respectively.