Preparation of calcium oxide from crab shell through decompotition at 3 hours at various temperatures 700°C, 800°C, 900°C, 1000°C and 1100°C was done. Calcium oxide from preparation was characterized using X-Ray Diffractometer (XRD) , FT-IR spectrophotometer and SEM-EDX analysis. Calcium oxide from characterization was applied for biodiesel synthesis from waste cooking oil, palm oil and co…