Due to globalization, the demand for fossil fuels has exponentially raised and pollution level in ozone also increased. This causes awareness, leading the researchers to study about various renewable energy sources. In that extensive research, bio-diesel blends form a small part of business and are playing a vital role in developing an alternative fuel for automotive usage, which will be more efficient, balanced, and less pollutant. This research study deals with the use of a multi criteria decision making techniques called Analytic Hierarchy Process (AHP) and TOPSIS to analyse and rank the different blends of biodiesel from the engine performance data. For acquiring data, for ranking the biofuel, a 4-stroke test engine was fuelled with Pungam oil biodiesel and operated at various engine rpm and torques. The Analytic Hierarchy Process (AHP) is basically to analyse the performance and emission of the IC engine. Here, separate models are developed for emission characteristics. To rank the best fuel blend, the biodiesel blend percentage and engine load conditions are used as the input data, while the exhaust emissions parameters such as NOx, smoke, CO2, HC, etc. are considered as the output. From the comparison of results of the AHP-TOPSIS method, the B20 blend is the best option for low engine loads while B80 shows up as the best option at high engine loads. © 2021 Institute of Physics Publishing. All rights reserved.