Mould Volume Calculation

Have you ever had too much soap for your mould?

Or too little?

There's an easy way to find out how much oils are needed to fit the mould you're intending to use, no matter what size or shape it happens to be.

All you need is a ruler, the mould in question, a calculator, water, and a square or rectangular waterproof container.

For moulds that have a square or rectangular shape (the easy ones):

First, measure the length, width and height (or depth) of your mould in inches. The height can be whatever height you want your soap to be, it doesn't necessarily need to be to the very top of the mould.

Important: Make sure you measure the inside of the mould and not the outside!

Next, apply the following equation:

    Length x Width x Height x 0.4 = ounces of oils

Let's try it:

The length is 15 inches, the width is 3.5 inches and I've decided to have the "top" of my soap just below the lip of the mould. This makes the height 2.4 inches.

So, 15 x 3.5 x 2.4 x 0.4 = 50.4 ounces of oils

Rounding it to the nearest whole number makes it a 50-ounce mould. 

TIP: mark this value on your mould for easy reference!

 OK, but what if your mould is like this?

For irregular-shaped moulds (still the easy ones):

You could try to enlist the aid of a geometry wiz to develop all kinds of volume equations, but that's not very practical, or fun.

Instead, fill the weirdo mould with water up to the level where you want the top of your soap to be.
Then, pour the water into a square or rectangular container, such as a plastic tupperware container, or if you have a soap mould with a silicone liner, you can also use that. Just make sure it's waterproof, so
I'd stay away from cardboard boxes.

Now, we just have to measure our container as we did for the square/rectangular mould. The height in this case would be measured from the bottom of the container to the level of the water. Apply the equation and voila! You now know the capacity of your Bundt cake mould.

Right, then. Let's see what we get in practice.

 

And I didn't even spill any water! 

And now for the measurements.

As before, measure length, width and height, making sure to take the inside dimensions of the mould. All this is in inches as mentioned before. If you use other units, you won't get the weight of oils in ounces. You may then have to measure your oils in kumquats or turnip heads....

12 x 7.5 x 1.125 x 0.4 = 40.5 ounces of oils

So I'd round this down to 40 ounces of oils for a nice Bundt Soap!

Whew! That wasn't so bad, was it?