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Essential Oils and Blending - A Beginner's Guide

Have you ever wanted to learn about blending essential oils, but aren't sure where to start? Wanting to save some money and learn how to make diffuser blends yourself? Then keep reading - this is the perfect blog post for you!


Essential oils can be blended for many different reasons. Those include, but are not limited to, the following:

  • Creating Diffuser Blends - both for "smelling good" and for therapeutic uses

  • Designing Products - both for retail and for aromatherapist ailment usage

  • Using in Aromatherapy massage

  • Using in Aromatherapy client care

While blending essential oils for therapeutic uses and aromatherapist client care can get quite complicated, blending for diffuser use is actually quite easy!


There are two main ways to approach blending without having to have a lengthy chemistry background in essential oils - there is the method of utilizing blending factors, and the use of weighted percentages. While both have their advantages, they can also have their drawbacks too. Here is a quick overview on how each work!


Blending Factors are numbers assigned to each individual essential oil that categorizes them based on how strong they smell when you open their bottle. The stronger the smell of the oil, the less drops you need to create a blend - therefore that essential oil will have a lower blending factor. If the essential oil isn't as strong when you smell it straight out of the bottle, that means you will need more drops to create a stronger blend - therefore that essential oil will have a higher blending factor.

While the method of blending factors is great, it relies on number of drops to determine how much essential oil you need in a blend. For diffuser blends and using essential oils in a diffuser, this method is perfect! The drawback, however, is each bottle can have a different type of stopper, thus creating different sizes of drops depending on what bottle and what brand of essential oil you choose to purchase. This can lead to discrepancies between different brands, and can create slightly different smells when using them in a diffuser.


Weighted percentages are based on the top-middle-base method. The top-middle-base method is a series of percentages that help you determine a blend based on a top note, a middle note, and a base note. Top notes are the smells that you smell first when a blend hits your nose. The middle note is the second smell you smell after you've been running your blend for a while in a diffuser or burning in a candle. The base note is a smell that holds all the other smells together, and when used in a candle blend, is usually the last smell you smell as it burns.

The percentages come into play when you are creating candles or stronger blends - there are two options for top-middle-base percentages:

  • 50-60% top / 30% middle / 10-20% base

  • 30-40% top / 50-60% middle / 10-20% base

When creating candles, you need to take into account the actual weight of the essential oil 0 NOT the drops. When you know how much weight of essential oil you need to add to scent your candles, you can use the percentages listed above to figure out how much of each essential oil you need to add. This is a huge advantage in this specific method because you can get more precise blending every single time you create a product

The disadvantage to using this method is when you are creating essential oil blends for things like diffusers, you have to do unnecessary math and weighing out oils just to put a small blend into your diffuser.

This is why we at Ampersand Essential Oils created the third blending factor method that we use most often - the Weight by Factors Method!


The Weight by Factors Method is very new to the industry, but combines both the blending factor and weighted percentages method of blending! This is great for when you want to make essential oil diffuser blends in bulk and know what size of bottle you want to use!

The way the Weight by Factors Method works is by first figuring out what essential oils you want to use in your blend. Let's take this Cozy Vanilla blend as an example:

Vanilla CO2 (Vanilla planifolia)

Cedarwood-Himalayan Essential Oil (Cedrus deodara)

Cinnamon Leaf Essential Oil (Cinnamomum zeylanicum)

After you figure out what essential oils you want to use in your blend, you then write down the size of bottle you want to use. For this example, we will use a 1 fl oz dropper bottle.

Next, you need to figure out what the blending factors are for each essential oil. The blending factors for each essential oil listed above are as follows:

Vanilla CO2 (Vanilla planifolia) - BF 2

Cedarwood-Himalayan Essential Oil (Cedrus deodara) - BF 4

Cinnamon Leaf Essential Oil (Cinnamomum zeylanicum) - BF 3

On average, 1 fl oz of oil is approximately 29.57g in weight (take note, we are converting US fl oz to metric grams here). While this does depend on the actual essential oil, we are simplifying this method for understanding for now!

Next, you add all the blending factors together. In this case, it would be 2 + 4 + 3 = 9. This is the total blending factor of the entire blend.

After this, you divide each essential oil's individual blending factor by the total blending factor. It looks something like this:

Vanilla CO2 (Vanilla planifolia) - BF 2 --> 2/9 = 0.222

Cedarwood-Himalayan Essential Oil (Cedrus deodara) - BF 4 --> 4/9 = 0.444

Cinnamon Leaf Essential Oil (Cinnamomum zeylanicum) - BF 3 --> 3/9 = 0.333

You then multiply each of these numbers by the total number of grams in weight to get the number of grams of each essential oil required to make the blend. It looks something like this:

Vanilla CO2 (Vanilla planifolia) --> 0.222 x 29.57g = 6.57g

Cedarwood-Himalayan Essential Oil (Cedrus deodara) --> 0.444 x 29.57g = 13.14g

Cinnamon Leaf Essential Oil (Cinnamomum zeylanicum) --> 0.333 x 29.57g = 9.86g

You then weigh out each individual essential oil using a food scale, add each essential oil to the 1floz dropper bottle in the order listed, put on the cap, and shake vigorously for at least 30 seconds.

And voila! You now have a larger bottle of the diffuser blend you love, created and measured at the correct blending factors, while also taking into account the actual weight of each individual essential oil!

We hope this blog post was helpful for you in creating and crafting your own essential oil blends! If you have any questions, please don't hesitate to reach out to us!

Stay safe,

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