Recipe vs. Formula…What’s the difference?

A recipe…

1. Is less precise (ex. units of volume as measurements like cups/tsp/drops)
   1. This does not account for specific gravities and variations in densities between ingredients
2. Does not account for usage rates on limited materials (ex. Active surfactant matter, fragrance, preservative, etc.)
3. Cannot easily be scaled up or down
4. Results in different outcomes batch-to-batch based on inaccurate measurements and substituted ingredients

A formula…

1. Is precisely measured using units of mass (ounces, grams, etc.)
2. Can be standardized with a set list of ingredients and processing instructions
3. Produces consistent results
4. Is easily scalable 

Recipes are a good place to start if you’re new to making soaps, candles, bath bombs and more. They are accessible and easy for anyone to understand, regardless of experience. Recipes are ideal for hobbyists who are making products for themselves, family, or friends. However, recipes can produce inconsistent results and are hard to scale up or down. For example, a recipe may call for one cup of coconut oil…even if you level the cup after scooping the coconut oil, you might get a little bit more or little bit less in the measuring cup anytime you follow the recipe. Even the smallest differences in measurements can affect the final product. Again, this is okay if your creations are for personal use, but you might want to consider switching to formulas so they are consistent from batch to batch. Consistency is crucial for small and large businesses. A formula will produce reliable results, along with allowing you to make precise adjustments necessary to improving your final products.

What Do You Need to Start Formulating?

• Precise kitchen or laboratory scale
• Calculator (there’s probably one in your pocket right now *wink wink*)
• Some basic math skills

How to Convert a Recipe to a Formula

1. Measure out your ingredients individually by weight using a scale
   1. Make sure your unit of measurement stays consistent! If you weight one ingredient in grams or ounces, stick with that unit for all other ingredients
2. Record the weight of each ingredient in a format that is easy to refer back to (phone notes, excel table, pen and paper…whatever is easiest for you!)
3. Add up the weights of all the ingredients so you know the total weight of the formula
4. Divide the weight of each individual ingredient by the total weight to find its percentage value
   1. Here’s a quick refresh on getting percentage values from decimals: Divide the part (the weight of the individual ingredient) by the whole (the total weight of the formula). Move the result decimal point twice. That’s the ingredient percentage! 
      1. I.e. 3 / 10 = 0.3 = 30%
5. Add up all the percentage values so ensure they total to 100%
   1. Round up or down to the nearest decimal point if necessary to get a formula that totals to 100%!
6. List out the ingredients’ percentage values and admire your work!

How Do You Use a Formula?

Once you’ve converted your recipe to a formula, you can use the percentage values to scale the recipe up or down to account for the amount of ingredients you have on hand, the batch size you want to make, and/or the order volume you need to fulfill. A formula gives you the exact measurements you need to get a set amount of total product – quickly, easily, and accurately.

To apply your formula, determine how much of a product you’d like to make. Then, calculate the percentages of that total using the values for each ingredient to find out how much you’ll need to measure out. 

To do so, multiply the percentage (in decimal form) of each ingredient by the total desired weight of the product to find the individual weight of that ingredient. To make more or less of a product, simply change the total final weight of the formula and recalculate the ingredient percentages based on that total! 

Putting it All Together

Let’s create a formula from a recipe and then scale it up and down! Here’s a bath bomb recipe that we love and want to turn into a formula so it’s more precise. First, we’ll measure out each of the ingredients onto a scale so we know their exact weight in grams so they can be weighed out to the same amount each time we make bath bombs. 

Dry:

• • 2 cups Baking Soda = 553 grams
  • 1 cup Citric Acid = 238 grams
  • 1/2 cups Arrowroot Starch = 75 grams

Wet:

• • 3 tsp. Fragrance Oil  = 9 grams
  • 2 tsp. Polysorbate 80 = 8 grams
  • 1 tsp. Cocamidopropyl Betaine = 4 grams
  • 1 tsp. Glycerin = 5 grams

Adding up all the individual ingredient weights gives us a total of 892 grams. Now, we’ll divide each ingredient’s weight by the total weight.

• • Baking Soda: 553g/892g = 0.62
  • Citric Acid: 238g/892g = 0.267
  • Arrowroot Starch: 75g/892g = 0.084
  • Fragrance Oil: 9g/892g = 0.011
  • Polysorbate 80: 8g/892g = 0.009
  • Cocamidopropyl Betaine: 4g/892g = 0.004
  • Glycerin: 5g/892g = 0.005

Next, we can convert each decimal value to a percentage by moving the decimal points over to the right two spaces.

• • Baking Soda: 0.62 = 62%
  • Citric Acid: 0.267 = 26.7%
  • Arrowroot Starch: 0.084 = 8.4%
  • Fragrance Oil: 0.011 = 1.1%
  • Polysorbate 80: 0.009 = 0.9%
  • Cocamidopropyl Betaine: 0.004 = 0.4%
  • Glycerin: 0.005 = 0.5%

Don’t forget to add up all the percentages to make sure they equal 100%! Round to nearest decimal point if necessary. And now you have a formula! Here’s what it looks like written out…

• • 62% Baking Soda 
  • 26.7% Citric Acid 
  • 8.4% Arrowroot Starch 
  • 1.1% Fragrance Oil 
  • 0.9% Polysorbate 80 
  • 0.4% Cocamidopropyl Betaine
  • 0.5% Glycerin

Using these percentages, we can quickly find out exactly how much of each ingredient we’ll need to make…whether it’s one or one hundred! You can also change the units of weight used to measure the ingredients using a formula. In our original example, we made 892g of bath bomb mixture in total. But, let’s say we wanted enough bath bomb mixture to fill five 8 oz. bath bomb molds. That’s 40 ounces in total. We can multiply the ingredient percentages (in decimal form) by 40 to find their individual measurements in ounces. 

• • 62% or 24.8 oz. Baking Soda 
  • 26.7% or 10.68 oz. Citric Acid 
  • 8.4% or 3.36 oz. Arrowroot Starch 
  • 1.1% or 0.44 oz. Fragrance Oil 
  • 0.9% or 0.36 oz. Polysorbate 80 
  • 0.4% or 0.16 oz. Cocamidopropyl Betaine
  • 0.5% or 0.2 oz. Glycerin

Now we can make 40 ounces of bath bomb mixture in total to get exactly how many bath bombs we need! 

Additional Benefits of Formulating in Percentages

1. Helps you account for IFRA limits by comparing your fragrance usage percentage to the limits outlined in the IFRA compliance documentation
2. Gives you the ability to make small tweaks based on percentages in a way that’s easy to replicate

In conclusion, transitioning from simple recipes to percentage-based formulas offers unparalleled benefits in precision, scalability, and batch-to-batch consistency. By focusing on mass and ratios rather than volume, you ensure professional-quality results every time you create. Start converting your favorite recipes today to take full control of your formulations and grow your craft with confidence!

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