Soap making

Soap recipes are shared in percentages because percentages travel between batch sizes without changing the soap. But you cannot weigh a percentage.

Sodium lactate for a harder bar, clay for slip, oats for a gentle scrub, a spoon of honey for label appeal. Additives make a soap recipe your own, but

You know what a batch of soap costs you in oils and lye, but that is not the number you need. What you need is the cost of a single bar, and then a price

You have a soap recipe that works, and now you need it in a different size. Maybe the mould changed, maybe you are doubling for a market, maybe you want

A bar of cold-process soap weighs more on the day you unmould it than it will on the day you sell it. Over the cure, water evaporates and the bar shrinks and hardens.

After you cook a batch of liquid soap, what comes out of the pot is a thick amber soap paste, not the pourable soap you actually use. That paste has to

The melt and pour batch calculator works out how much soap base a mould needs to fill it, then the fragrance and colour to match, all from the mould volume

The soap colorant quantity calculator works out how much mica, oxide or natural colour a batch needs, based on the weight of your oils, and gives the amount

The soap fragrance usage calculator turns a fragrance load, given as a percentage of your oils, into grams for the whole batch and grams per bar, and checks

The soap mould volume calculator works out how much oil a recipe needs to fill a given mould, using the mould’s shape and dimensions, then tells