How to make blends according to % concentrations?

For example, how do you figure out a 3% concentration of your essential oil in 29 milliliters of carrier oil?
Any and all questions by those needing a little help, and sharing by those who've been there :)
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How to make blends according to % concentrations?

Post by MelissaGinger » Wed Jun 29, 2011 7:39 am

Hi -- I see a lot of recipes I'd like to make which use a percent (%) of essential oil in a carrier. Can you explain how this is measured?



Re: How to make blends according to % concentrations?

Post by puresimplecure » Wed Jun 29, 2011 8:04 am

Percentages are pretty easy really. It's more simple if you do your blend according to milliliters rather than ounces. So here are some things you need to know:

There are 30 milliliters ("ml") in 1 ounce.
There are between 30 and 35 drops of essential oil per milliliter. I've measured several ways. With the graduated plastic measuring pipettes, I get 30 drops per ml, and a glass eye dropper, with the same oil, I get 35.

This was a fairly 'thin' oil, but the results will be close with other oils regardless.

SO, you can measure for yourself using an eyedropper with markings on it, or a graduated pipette. Or, just assume 32 drops per milliliter and don't worry about the little differences -- it really shouldn't matter in the final product anyway!

To figure the number of drops for each 1% concentration:
Start by figuring that 3ml in 30ml is 10% -- that's 96 drops essential oil in a total one ounce of blend. This can be done by adding the essential oil to the mixing bottle first (we'll assume we're using a 1oz mixing bottle), then fill the rest of the way -- slowly and carefully! -- with your carrier oils.

If 96 drops is 10% in one ounce, then 9.6 drops is 1% in one total ounce of blend. Use 10 drops from a glass eye dropper, and 9 from a graduated plastic pipette (see

Remember, 10% is just to show the math -- it's a pretty high concentration used in fairly rare cases....

1% in one ounce is 10 drops total essential oil
2% is 20 drops
3% is 30 drops
4% is 40 drops
5% is 50 drops

and so on. Of course, to make larger blends -- 4 ounces, for example, just multiply the number of drops by four.

Hope it helps! :geek:

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Re: How to make blends according to % concentrations?

Post by Trisht » Wed Jun 29, 2011 11:38 am

i used this chart to determine percentages when i was taking course work with ACHS... sorry i dont have a reference for the source and please note the formatting has slightly shifted so the columns are for 1%, 2%, 4%

Carrier or Base Oil Volume/dilution %

(dilutions) * 1% **2% ***4%

1/2 oz (1 Tbsp)/ *3 drops/ **6 drops/***12 drops

1 oz (2 Tbsp)/ 6 drops/ 12 drops/ 24 drops

2 oz (4 Tbsp)/ 12 drops/ 24 drops/ 48 drops

4 oz (1/2 cup)/ 24 drops/ 48 drops/ 96 drops

8 oz (1 cup) 48 drops/ 96 drops/ 192 drops

16 oz (2 cups) 96 drops/ 192 drops/ 384 drops

additional info from my "conversions and dilutions" document:

1 cup = 8 fluid ounces (8 oz) or about a quarter of a liter, or about 235 milliliters (236.58 ml)
1 ounce = 2 tablespoons (2 Tbsp), or just under 30 ml (about 29.57 ml)
1 Tbsp = 3 teaspoons (3 tsp), or just under 15 ml (about 14.78 ml)
1 tsp = just under 5ml (about 4.92 ml)
1 dram = 1/8 of a fluid ounce, or about 3.7 ml
4 oz water = approx 120 ml
20 drops = 1 ml
30 drops EO = 1.5 ml

hope it helps!


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Re: How to make blends according to % concentrations?

Post by Ananda Staff » Wed Jun 29, 2011 6:53 pm

:D Wow -- thanks for that. So many folks have tea- and tablespoons and cups available for measurement, but not graduated eye droppers or scientifically inspired pipettes.

The only thing that I'd like to truly be sure of is the number of drops per ml that you list (20). Until a year ago, I thought that number had to be right, because I saw everywhere -- as the value for "water". It seemed everyone in the aromatherapy world assumed (including myself) that this must be the case for oils.

Yet EVERY MEASURING DEVICE I've used in the course of practice at The Ananda Apothecary has shown a minimum of 30 drops of oil, and often times 35 or 36. I've used several plastic disposable transfer pipettes, as well as eye glass droppers with gradations on them. Just for the heck of it, I JUST tested again -- three separate devices, a new glass eyedropper graduated to 1ml by .25, and a new plastic pipette, graduated to 3ml by .5ml, and an undergraduate new glass eye dropper with which I re-measured the amount of oils which came out of the first two devices. Using dark patchouli, each device resulted in 36 drops per milliliter.

I know what you've posted is a copy of information that has been in use for some time. Though being a professional practitioner, I think it important as a community we consider that we may have the wrong data. MAYBE the 20 drops per ml comes from a specific scientific dropper? It doesn't change significantly enough between oils, and even water, with the tools we -- or at least "I" use, for it to be a factor of conditions: viscosity, heat, etc.

With an open mind, and desire to help the aromatherapy community, especially as more and more turn toward "aroma-medicine" this is what we've recently posted on The Ananda Apothecary.

I'd be VERY interested in others' experience with this same experiment, and any factors they think might be affecting the results, as this is certainly an important topic, and we'd like to get it straightened out. :?: Thank you akrno.

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Re: How to make blends according to % concentrations?

Post by Lady Mac » Sat Jul 09, 2011 7:33 pm

I have been searching to find out where I got the information I have in my blending notebook, and I apologize that I can not find the source of this. It was a textbook that was used in an aromatherapy class, but I can not give credit where credit is due. The basic formula I learned was that all e.o's have a blending factor. Powerful aromas are "1", more volatile are higher on the scale, for instance peppermint, thyme, melissa, lemongrass are "1", lavender, orange, bergamot are a "7". The information I have says 1 oz = 30 cc = 2TBS = 600 drops. A 1% dilution would be 6 drops of essential oil to 1 oz carrier. Hence 3% would be 18 drops. To determine how many drops of e.o. to use is a combination of three things - math, intuition, and knowledge of the person who will use the blend, either yourself or a loved one. The math is fairly easy: add the blending factors of each oil together, divide the individual blending factor by that total, multiply that total by the number of total dilution drops. As an example, a muscle rub of rosemary, eucalyptus and peppermint in a 3% dilution would have the following recipe

Rosemary, blending factor of 2
Eucalyptus, blending factor of 4
Peppermint, blending factor of 3 2+4+3 = 9 2 divided by 9 = .22 4 divided by 9 = .44 3 divided by 9 = .33 .22 x 18 = 3.96 .44 x 18 = 7.92 .33 x 18 = 5.94

In cases of fractions, you would round the drops up, so 4 + 8 + 6 = 18, which is the 3% solution ratio.

I have the blending factors for about 48 essential oils, if anyone is interested.

Your intuition is honed by experimenting, so always write your formulas down, even the icky "what is this?" ones, always test a small amount first, ask questions (do you have any allergies, how sensitive are you) of yourself and any loved one and practice safety.

I hope that you will find this useful, and not too confusing. I will continue to look for the source of this information. Thanks!

Lady Mac
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Re: How to make blends according to % concentrations?

Post by Lady Mac » Mon Jul 11, 2011 6:34 am

The source of the information I posted was from "Aromatherapy for Body Workers" by Jade Shutes and Christina Weaver. It is a textbook (available on-line from several sources) but is really excellent reading.

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Re: How to make blends according to % concentrations?

Post by Edgar » Sat Jul 30, 2011 10:34 am

Wow, I really like the blending factor approach idea. It's certainly true that oils for ANYthing, diffusing, skin care, other medicinal purposes, have different "intensities". If you're experienced, its easier to do it by intuition - thanks for the book post too. When you're getting started, its good to have recipes, and the more you make, the more you become familiar with what might be called "blending factors". Except the 18 drops = 1% part, as ever time I've measured, I've gotten about 30 to 35 drops per milliliter, which is 1/30th of an ounce; which is about 3%. I wonder if I'm doing something wrong, or maybe the scientific number of 20 drops per ml is from the use of very specifically-sized droppers, not like a regular eye dropper. Have you had the chance to measure?

Thanks Lady Mac!

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Re: How to make blends according to % concentrations?

Post by Lady Mac » Thu Aug 04, 2011 11:23 pm

Hi MelGinger! I can only tell you about my personal experience with measuring, and of course, it may not be what works for you, but I don't use a regular eye dropper. I blend directly from the essential oil bottle using the orifice reducer that comes with it. The plastic top that "drips" the oil out. They have a standard opening, and uses gravity, so I'm not dependent on the pressure of my fingers on the eye dropper bulb. The e.o. drops are usually smaller than the drops from an eye dropper, so that may be a factor in your measuring versus mine. Also, the orifice reducers help in other ways - they provide additional protection from air and moisture, and if you knock your bottle over they prevent major spills. Anyway, I don't think you are doing anything "wrong" with how you measure - if you are comfortable with your formula, and have an idea of what your base percentage is, like your example says, then play around with it to adjust. Start with blending a smaller amount, then let your intuition and sense of smell guide you. Blend your essential oils first, swirl them gently to mix, then let them rest. I personally let them synergize for at least 15 minutes - that gives my nose a rest and lets them mingle. Then I go back to them and see if they are "right", and then I add my carrier oil(s), or adjust the formula and let it rest again. Remember the carrier oil is just as important as the essential oils and some carrier oils will add their own "scent", or flavor to the blend. A good way to see if oils will "marry" together well before you blend them is to open the bottles, hold them together and pass them under your nose a few times. That way you can get a better sense about the blend before you actually blend. Essential oils work through inhalation as well as through the skin, so sometimes just smelling the oils first will trigger a response, if you recoil from the odor chances are it's not for you! Plus, that gives you an idea of which oil is going to dominate and you can figure a percentage from that. Gosh, I don't know if this answered your question, I love talking about essential oils and blending, and I have a tendency to tangent out but I hope it helped!

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Re: How to make blends according to % concentrations?

Post by Ananda Staff » Sat Aug 20, 2011 3:39 pm

We've spent some time and measured the drops per milliliter of each essential oil in the store, using a pipette that delivers 20 drops per ml of water.

The table makes it easy to measure fractions of milliliters, as well as more precisely calculate % concentrations -- or the amount of essential oil needed to make these concentrations.

Here's the table with drops per milliliter of each essential oil -- again, this depends really on the device being used, but will be accurate with standard glass eye droppers and pipettes.


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Re: How to make blends according to % concentrations?

Post by Sue Cruz » Sat Aug 20, 2011 6:01 pm


Thanks for the "Drops Per Milliliter Essential Oils Chart"! And thanks for the explanation as well. It's perfect! I'll be putting it to good use.

Warm Regards,


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Re: How to make blends according to % concentrations?

Post by Ananda Staff » Sat Sep 24, 2011 4:46 am

I did just learn the 3ml pipettes are rated for 22 drops of water (likely at 68degF). This is just to give a basis for the numbers on the drops-per-ml chart of essential oils.


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Re: How to make blends according to % concentrations?

Post by Lady Mac » Mon Sep 26, 2011 9:30 pm

Merlin - I got this information from "Aromatherapy for Bodyworkers" by Jade Shutes and Christina Weaver, copyright 2008 by Pearson Education, Inc., one of the textbooks used in an aromatherapy class I took. It covers blending, chemistry, integration, how to read data sheets, special populations and settings, and reviews carrier oils, among other things. The blending factor list is a concept taught at the Raworth Centre of Natural Medicine in England (per the authors). "The blending factor is by no means written in stone . . . we acknowledge that essential oils vary in strength from company to company, from year to year, harvest to harvest, and so forth. So one should feel free to adopt different blending factor numbers based upon a comparison with other oils of stable potency, such as Roman chamomile or neroli, which would always be more potent, or citrus oils which are always more volatile and lighter (Page 92, Chapter 5, Aromatic Blending). In this list a blending factor of "1" is a powerful aroma, so use less, and a "10" is more volatile, use more. Please note, in cases where there may be more than one species used for oil I have indicated the botanical name. Hope you find the info useful!

Angelica (archangelica) - 2 to 3
Basil (ocimum basilicum)- 4
Bergamot - 7
Birch - 2
Black Pepper - 3 to 4
Cardamon - 4
Carrot Seed - 6
Cedarwood - 5 to 6
Roman/German Chamomile - 1
Cinnamon - 3
Clary Sage - 2 to 3
Clove - 5
Cypress - 5
Eucalyptus (globulus) - 4 to 5
Fennel - 3
Frankincense (boswellia carterii)- 3 to 4
Geranium (pelargonium graveolens) 3
Ginger - 4
Grapefruit - 6
Helichrysum (italicum) - 5
Jasmine (officinale) - 1
Juniper berry - 4
Laurel, bay - 2
Lavender (angustifolia) - 7
Lemon - 4
Lemongrass - 1
Mandarin, tangerine (citrus reticulata) - 7
Marjoram, sweet - 3
Melissa - 1
Myrrh (commiphora myrrhanee) - 4 to 5
Neroli (citrus aurantium)- 2
Niaouli - 2
Orange (citrus sinensis) - 7
Palmarosa - 4
Patchouli - 5
Peppermint - 1
Petitgrain (citrus aurantium) -4 to 5
Pine, Scots (sylvestris) - 4 to 5
Ravensara - 7
Rose (Rosa x damascena) - 1
Rosemary (officinalis) - 2 to 3
Sandalwood (santalum album) - 6
Spearmint - 2
Tea Tree - 3
Thyme (vulgaris) - 1
Vetiver - 1
Yarrow - 3
Ylang ylang - 4

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