Select Oil/s
Total of oils


Please read instructions below before using calculator.
SuperfatNaOHKOH
0%00
1%00
2%00
3%00
4%00
5%00
6%00
7%00
8%00
9%00
10%00


PercentWater
25%0
30%0
35%0

PercentFragrance
2%0
2.5%0
3%0

  • Download an Excel Spreadsheet version of the OzCalc for use off line.

  • To use select your choice of oil, fat or butter from the pull down menus and add the required weight value in the box next to it. Continue until all the oils, fats, butters etc you are using have been added. click on Submit to display the recipe. PLEASE NOTE: The NaOH sap value for coconut oil has been updated to a milder figure as per general consensus in the international soaping community. Lisa WB August 06

  • This calculator works with both ounces or grams. Your recipe will work fine as long as you don't mix the two! ALWAYS work in one or the other, never both, it only leads to potential soap disasters.

  • All units of measurement are by weight, not volume.

  • Values for both NaOH (caustic soda, sodium hydroxide, lye ... for hard soap bars) and KOH (potash, potassium hydroxide, lye ... for liquid soap) are provided in these calculations. Please take care to ensure that you are using the appropriate value for your recipe.

  • 30% water/liquid portion is quite suitable for the majority of NaOH (bar soap) recipes. If using a tricky fragrance oil use 35% water/liquid as this gives more time to manage the reaction. If you are an experienced soapmaker you may prefer to discount your water and use the 25% value.

  • We recommend using the 35% water rate for KOH (liquid soap) recipes to liquify your caustic. The dilution water rate should be the initial water rate x 6 (minimum) or x 8 (maximum). This is a good website which explains the liquid soapmaking process Essence Supply.

  • 2 1/2% is a good standard for most fragrances. 3% when using the weaker scents. 2% if using strong scents, particularly potent essential oils. In fact some essential oils, such as lemon myrtle and other ones, should not be used at more than 1%. Please use your supplier's recommendations when formulating your scents.

  • Whilst all care has been taken to ensure this calculator is as accurate as possible, no responsibility can be accepted by the creators of the calculator, or the owner of this page, for any damage, injury or errors resulting from the use of this calculator. Be aware that NaOH and KOH are caustic in nature and take appropriate precautions to prevent accidents.

  • The OzCalc Soap Calculator has been written by Paul and Lisa Wood-Bradley. Copyright 2003/2004.