Due to mostly economic reasons, different countries of the world use different raw materials in biodiesel production. Since the fatty acid distribution of the raw material used in biodiesel production remains almost the same during the transesterification reaction, the biodiesel raw material has a critical effect on the fuel properties of the obtained biodiesel. Therefore, the Physico-chemical properties of biodiesel fuels produced from different raw materials will be different. Among many different fuel properties, one of the most critical is the cetane number of the fuel. The cetane number, which directly affects all engine properties and is one of the most critical chemical properties of diesel/biodiesel fuels, is an important indicator of the flammability of the fuel. Ignition delay time, which can be defined as the time interval between the start of fuel injection and the start of combustion, decreases with increasing cetane number, thus limiting the rapid increase in in-cylinder pressure and temperature values. The cetane number of a fuel is measured using a cetane engine. However, since the cetane motor is a very expensive device and the determination of the cetane number is time-consuming, it can only be used in a very limited number of research centers. Instead of the cetane number, the cetane index can be calculated with a negligible margin of error. The cetane index of a fuel is an alternative parameter to the traditional cetane number used to characterize different types of diesel fuel. In this experimental study; 11 different biodiesel fuels were produced from safflower oil, sunflower oil, hazelnut oil, rapeseed oil, corn oil, palm oil, cottonseed oil, soybean oil, olive oil, waste frying oil, and algae oil, and Calculated Carbon Aromaticity Index (CCAI) depending on the cetane index of these fuels. The) change was taken into account.