Lets pull out our rulers and calculators for a moment and discuss the size and ounces for a soap bar...
Using a rectangle shape for our soap bar design, we need to find out what dimensions we need to get a soap bar the ounce weight or volume we would like. The length, width and thickness or depth of the soap bar lets us know what the cubic measurements of the soap bar are going to be. Say I would like my soap bar to measure 3.5" long x 2" wide x 1" thick. 3.5 times 2 times 1 equals 7 and since we used inches as our measurement choice the rectangle shape would have 7 cubic inches. Converting the cubic inches to ounces lets us know that a rectangle that is 3.5" x 2" x 1" thick would create a soap bar that is about 3.878787... ounces in volume.
Now we need to look at the ingredients that will be used in the formula and the ounce volume of the oils which weight more than water volume, the water in the formula (knowing some will evaporate when bringing the soap to the trace temperature), and anything else that may be added to the soap bar formula such as an abrasive (seeds, flower petals, bark, an embedded toy for kids, et all). All of these ingredients can add to the weight of the soap bar. Our design choices as well can remove some volume or weight to the soap bar such as rounded corners or a rounded surface edge, and engraving into the surface. Some design details may add volume or weight to the soap bar such as raised artwork/company logo on the surface and raised borders on the surface of the soap bar.
When we design a soap bar and a client would like their soap bar to be around say 3.5 ounces and it is to be a rectangle with the dimensions 3.5" x 2" x 1" thick, we could round the corners (should the company/artwork logo compliment the choice) and that would decrease the volume placing the soap bar within the minimum range of weight or volume needed.
When a product is labelled with a weight, the contents of the package must have at least the weight labelled on the package. Should the soap bar weigh a little more than the package, that is acceptable to the labeling laws and FDA regulations. It is when the contents weigh less than the label, a company would face fines. As we know, it is priority to get as close to the weight as we can knowing there is a minimum the soap bar has to be but not so much over that it costs more to manufacture the soap bar. A conversation with the client lets us know should they be adding an abrasive or object to the soap bar which helps.
One of our suggestions for a company already manufacturing soap bars and would like to have their company logo/artwork and a shape to their soap bar is to measure the length, width, and depth or thickness of the soap bar they are manufacturing and weigh the soap bar to know that is the ounce weight they would like. We can use those measurements to create their design for the new soap bar. We can use the dimensions and weight and even change the shape once we have the information. We at Masterline Molds, as a policy, do not ask about the details of a company's soap bar formula so by having existing weights and measurements of a product, we can use that information to create any shape and size for a soap bar design.
The measurements of a package or box are good to use as well when creating a soap bar design as we need to make the soap bar fit within those dimensions.
For a Square Shape Soap Bar 2" x 2" x 1" thick, the soap bar would be 4 cubic inches which is about 2.21645...ounces and a Cube Shape Soap Bar 2" x 2" x 2" would be 8 cubic inches or 4.4392...ounce. You can see that be changing the thickness can increase dramatically the cubic inches or ounces a soap bar may contain.
