The purpose of this research is to examine the ability of the buoyancy weighing bar method in determining the separation time of biodiesel and glycerol in various types and shapes of rods. In this research, the ratio of biodiesel and glycerol concentration is 99%: 1%. The types of rods used are made of bronze, copper, iron, aluminum with a diameter of 10 mm and a length of 210 mm, and the shape of the rod used is rectangular, cylinder, and sheet. This research is carried out at room temperature and used the results of gas chromatography analysis as a comparison. The results obtained indicate that the buoyancy weighing bar method can estimate the separation time of glycerol in biodiesel in various types and shapes of rods. The most accurate type of rod in predicting the separation time of glycerol in biodiesel is copper, while the shape of the rod does not provide a significant difference in estimating the time of separation of biodiesel and glycerol.