Skincare Formula Calculators

You may have started DIY your own skincare but mostly following through the recipes listing in drops, cups, teaspoons, etc. I started that way, and I’m also a huge believer in essential oils, so dilution is mostly counted in drops with carrier oils in volume. Measurements in volume tend to be less accurate than in weight, due to the specific gravity of each ingredient is not taken into account. This is why it is always best to formulate in percentage and work out the weight-based formula of the batch size of your natural cosmetics.

Calculation in Percentages

The formula should look like this:  







Shea Butter





Mango Butter





Rosehip Oil




Vitamin E

Additive – Antioxidant







1.  Decide on the batch size of your product you want to make

2. Based on the formulation composition, decide on the percentage of each category and function

3. Work out the weight-based formulation

For the example, the total weight (batch size) of the recipe is 50g

[% ingredient divided by 100%] x total grams

A = Percentage of ingredient (%)
B = Total weight of the batch size (g)

(A / 100%) x B

The shea butter is decided at 54% of the total weight so the calculation will go: –

54 (%) / 100 (%)x 50g = 27g

Repeat for each ingredient to finish your percentage formula. Check your calculation afterward as it should always add up to 100% (give or take a tiny decimal place). Practice with a few different formulas and quantities to get used to using the formula.

Volume versus Weight

You cannot mix volume (mL) and weight (g) at the same time. You must work either only in grams (solid mixtures) OR in mL (liquid products only). You cannot assume that 1 gram equals 1 millilitre for your ingredients.

If you mix the 2 measurements in one formula, your percentage calculations will be wrong.

– Volume only is fine for: facial toners and mists, body sprays, facial oils where only liquid oils and essential oils are used.

– Weight is necessary for: creams, lotions, scrubs, masques, butters, balms, massage bars, facial oils and serums that contain some solid butters.

However, to keep things simple and more accurate, it is recommended that you measure everything (even liquid formulas) in grams.

General Recipe Formula Calculator

The best thing is you can use the Formula Calculator spreadsheet with built-in calculations and formulas which will do all the hard work for you. The spreadsheet records your formulas as percentages and how to convert that formula into any amount (by weight).

It also comes the warning alert to give a useful reference of your formula to ensure each category of the ingredients is within the recommended range.
*The warning alert only serves as a reference. You will have to keep trying and experiment to create your own products. Making your own skincare or formulating cosmetics can be fun and very creative!

Emulsion Calculator

Make beautiful lotions and creams with this handy calculator!

The water phase (hydrophilic) and the oil phase (lipophilic) of an emulsion cannot be combined homogenously without an emulsifier. With the addition of emulsifiers, the surface tension at the interface between these two phases will be reduced, forming interactions with hydrophilic and lipophilic molecules. Emulsifiers are the connecting link between water and oil phases.

There are 2 types of emulsifiers.

1. Oil-in-water (o/w) emulsifiers keep oil drops packed in water
2. Water-in-oil (w/o) emulsifiers keep water drops packed in oil.

The main difference between the 2 emulsions is the proportion of the liquid phase is higher in O/W emulsions. W/O emulsions have a high oil concentration, whereas O/W emulsions have a low oil concentration.

O/W emulsions tend to be less cost-effective, as oils are always more costly than water and these type of emulsions are generally more challenging to produce. O/W emulsions are generally, more stable to make and Emulsion Calculator is designed for this is the type of emulsion.

The Emulsion Calculator is an Excel Worksheet that quickly and easily allows the formulator to calculate the requirements for emulsion.

This calculator requires only the input of the ingredients and percentages and will save much precious time to calculations by hand. The calculator is made up of 3 parts. All ingredients are added to the phases by using the available drop-down menus. By entering the size of the batch, the weight of each ingredient for the formula will be calculated. Next, print out the page and the recipe is ready!

Water Phase: Enter all ingredients that go into the water phase. Since water percentage is automatically calculated, the total of the formula will always equal 100%.

Oil Phase: Enter all ingredients that would be included in this phase. Enter the percentage of each Ingredient, and both water and oil phases will be calculated.

Cool Down Phase: This phase is for antioxidants, fragrances, essential oils, and preservatives.

The Emulsion Calculator Excel Worksheet also provides a table on basic starter formulas for home-crafters for lotion, moisturizer and body butter for various skin types.

It comes the warning alert to give a good reference of your formula to ensure each category of the ingredients is within the recommended range.

The Emulsion Calculator is used by home-crafters or formulators who already know the basis of emulsification or are in the process of learning it. You can learn to make homemade lotion cream by will following the key steps on creating an emulsion as well as formulas.

The built-in calculations and formulas will do all the hard work for you. The worksheet records your formulas as percentages and convert that formula into any amount (by weight).

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