Soap Calculators

10_03_000659aThe Handcrafted Bath & Body Guild welcomes both Professional Business Members and Casual Crafters, so our posts are going to cover a range of topics. We will cover some basic tips, techniques, and concepts, as well as some more challenging ideas. We will also be bringing you news from the cosmetic world, Health Canada, the International Fragrance Association (IFRA) and much more. If there is something you would like us to talk about, email us and we will be happy to oblige.

To start us off, we’re going to venture into the world of soap making, and take a look at lye calculators. It doesn’t matter how you find your way to the wonderful world of soap making, eventually you are going to find yourself staring at a lye calculator, saying “huh?”

So what exactly does a lye calculator do? 

In order to make a beautiful bar of handmade soap that does not leave your skin feeling like you’ve gone a couple of rounds with an electric sander, you need to make sure that you have no excess lye left in your soap when the saponification process has finished. If you’re shaking your head, and wishing for a quick lesson on saponification, zip over here for a crash course.

Okay, so the reason that lye calculators are so important, is that they will do all the math required to tell you exactly how much sodium hydroxide (lye) you will need to change all of your lovely oils into soap, without leaving any free lye left to irritate the skin. These days the Internet is full of sites offering up hundreds of recipes for hot or cold processed soap. Unfortunately, not all of them are well written. Before you try any recipe that you haven’t created  yourself using a soap calculator, take a minute to run it through one of these:

Soapcalc found at

In addition to the calculator, this site offers information on what different qualities our oils can give to a bar of soap, along with a sortable list of oils to help you find ones that contain those elements, a list of basic equipment needed, and FAQs for beginners. It also has a built in fragrance calculator.

Brambleberry Lye Calculator found at

Brambleberry has separate Lye and Fragrance Calculators, which is handy for people who are making something other than soap. Although this is a more stripped down Lye Calculator, it is fully functional, and connected to a wealth of information on soapmaking from The Soap Queen which is Brambleberry’s  ‘teaching’ arm, and a must visit for any beginning soaper.

If you’re all about your tablet or phone, there are a couple of Apps available that I have not tried personally, but I’m told they work well. They are Soap and Saponify, both of which are available for iOS or Android from your App store.

So that’s a quick summary….if you have another calculator that you swear by, leave me a comment and I’ll check it out.


3 replies
  1. Jasmine
    Jasmine says:

    I’ve been making soap for 2 1/2 years and I’m still using the Brambleberry Lye Calculator because the more advanced SoapCalc just leaves me scratching my head. Clicking on the help sections seems to just explain the bits I already understand. I’ve run into the “solution %” on other websites and other lye calculators but I have no idea what it means. I even found a forum that explained how to figure out the % that I soap at, but it just left me more confused. If someone could explain the finer points of these graduate level lye calculators I would really appreciate it !

  2. Marg
    Marg says:

    Hi Jasmine Thanks for commenting, and challenge accepted! The whole lye/water subject always causes a lot of confusion when it comes up in groups, so you’re definitely not alone. Off to sharpen my pencil (actually, turn on my iPad) so watch for a new post in the next couple of days.


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