Resizing your Formula to Fit any Soap Mould Size

Mis à jour : 25 mars 2020

Difficulty Level 1

Simple maths and calculations are an integral part of soap-making. One of the key skills we need in our toolkit is to know how to resize a formula to fit any size of mould.

How to Resize your Formula

Let assume this is an existing recipe that you want to resize to fit the capacity of a new mould. Note that the weights for water and sodium hydroxide are excluded from this formula as these are calculated seperately.

283 g Coconut Oil

425 g Palm oil

708 g Olive Oil

What is the percentage of each oil in the formula?

Converting into percentages

Firstly, you obtain a total weight in grams of all the ingredients in the formula

283 g Coconut Oil +

425 g Palm Oil +

708 g Olive Oil



Then you calculate the percentage equivalent of each ingredient in the formula by dividing by the total oil weight of the formula and multiplying by 100.

In this example, the total oil weight for the formula is 1416 and the calculations are as follows:

283 / 1416 * 100 = 19.98%

425 / 1416 * 100 = 30.02%

708 / 1416 * 100 = 50%

Your recipe now looks like this:

19.98% Coconut Oil

30.02% Palm oil

50% Olive Oil

Resizing the Recipe Down to Fit a Smaller Mould

Knowing the percentages for each ingredients is invaluable when it comes to resizing a formula.

Let's say we want to resize this recipe down to fit a small mould that can hold only 500 grams

19.98% Coconut Oil.

30.02% Palm oil.

50% Olive Oil

To convert the percentages into a gram weight, the small mould capacity of 500g is multiplied by each percentage to return an individual gram weight for the ingredients in the formula:

The calculation is as follows:

500 x 19.98% = 99.9 g

500 x 30.02% = 150.1g

500 x 50% = 250 g

Check to ensure that the total weight of your ingredients adds up to 500g

500 x 19.98% = 99.9 g +

500 x 30.02% = 150.1g +

500 x 50% = 250 g


500 g

Your recipe now looks like this:

99.9 g Coconut Oil

150.1 g Palm oil

250 g Olive Oil

Water & Sodium Hydroxide Quantities

All that is left to do is to calculate your water and sodium hydroxide quantities for this new formula of 500g of fatty acids.

If you are unsure of how to do this, refer to your handbook you received on the course or use an on-line calculator

The quantities for the above formula with 5% security margin are

Water . 190 g

NaOH . 69g

There you have it ! You can now increase or reduce your favourite formula to fit any mould size with ease !

1 vue0 commentaire

13 rue du château

82160 CAYLUS

Tarn et Garonne, France

Artisan Savonnière 

Expert Formatrice en SAF

Tél: +33 (0)

SIRET: 82892804400027

Le laboratoire Cosmetic Safety Assessment UK réalise les dossiers cosmétiques pour les savons Airmeith Savonnerie de Caylus selon le règlement Européen (CE) 1223/2009. Nous vous presentons nos savons avec un étiquetage conforme, destiné à vous informer  sur la nature du produit, sa composition, sa fonction, ses précautions d’emploi et ses conditions de conservation .

AVERTISSEMENT: Les informations sur nos produits sont données à titre informatif, elles ne sauraient en aucun cas constituer une information médicale, ni engager notre responsabilité. Pour tout usage dans un but thérapeutique, consultez un médecin.

  • White Facebook Icon
  • White Twitter Icon
  • White Pinterest Icon
  • White Instagram Icon