I am using 3" PVC as a mold. I have 3 11" lengths of 3" PVC that I was planning on filling to 10". I wanted to do 2 molds with my regular soap and add pumice to the 3rd. So I decided to do 2 batches. I used the "resize the recipe to fit your mold..." , entered 1.5" (radius) and 20.0" (height). The calculator said 28.27 oz (801.56g) of oil, that only filled one mold. When I manually calculate the oil, Pi*r(sq)*Height*.4 = oz of oil. I get 56.55 oz (1603 grm).