Calculating the Size/Amount to Fill a Soap Mold to help you to figure how much of a batch of soap that a mold will hold. Well what if you have the opposite problem? You know how much the mold will hold but your have a batch of soap that won't fit that mold? What do you do? I have the answer for you. Check out Lather Be Soaping's posting called Resizing and Converting Soap Recipes. In this posting discusses the reverse of adjusting your batch to fit into a mold that may hold a different amount of soap.