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Essential Oil Dilution Calculator for Hair

Enter your carrier oil and a strength to get the essential oil dilution for your scalp in drops — in total, per ounce and per tablespoon.

Jojoba, grapeseed, olive, castor — the plain oil the drops go into.

How strong should the blend be?

Drops are split evenly between them.

20 is the usual assumption. Droppers vary from about 20 to 30.

How to use the Essential Oil Dilution Calculator for Hair

  1. Enter your carrier oil

    Type how much carrier oil is in your bottle, in fluid ounces, milliliters or tablespoons.

  2. Pick a strength

    Two percent suits a leave-on scalp oil for most adults. Choose one percent if your skin is sensitive or the oil is new to you.

  3. Say how many essential oils you are blending

    Choose one, two or three oils. Leave the dropper setting at 20 drops per milliliter unless you know yours is different.

  4. Press “Count my drops”

    You get the total drops, the drops of each oil, and the drops per ounce and per tablespoon of carrier oil.

  5. Read the safety list before you mix

    Patch test first, keep the blend away from your eyes, and ask your doctor first if you are pregnant, breastfeeding or have a medical condition.

How to use the Essential Oil Dilution Calculator for Hair (58 s)

How the essential oil dilution for scalp oils is worked out

Essential oils are concentrated plant extracts. On the scalp they are always mixed into a plain carrier oil first, and the dilution is the share of essential oil in the finished blend. The calculator turns that percentage into something you can count: drops. 

essential oil (ml) = carrier oil (ml) × percent ÷ (100 − percent)
drops              = essential oil (ml) × drops per ml
drops of each oil  = drops ÷ number of oils

Which strength to pick

The four levels are the ones aromatherapy references use for skin: 0.5% and 1% for sensitive skin, 2% for an adult leave-on product and 3% for short contact. They are general conventions, not a promise that every oil is safe at that level. The safety reference by Tisserand and Young sets limits oil by oil, and some oils sit below 2%. Read the label of the oil you bought and use the lower figure.

Why drops are an estimate

The calculator assumes 20 drops per ml. Real droppers give roughly 20 to 30 depending on the tip and how thick the oil is, so you can change that number. Drops are also whole numbers. The result is rounded to the nearest drop, but if rounding up would add more than 15% extra essential oil, it rounds down instead. For very small bottles the tool tells you when even one drop would make the blend too strong, and how much carrier oil you need.

What the research does and does not show

People usually reach for rosemary or peppermint oil hoping for growth. Be realistic. One small six-month trial in people with pattern hair loss reported more hair in the rosemary oil group; it has not been repeated in large studies. The often-quoted peppermint oil result comes from a study on mice, which is not evidence in humans. A scalp oil can make a massage more pleasant and help dry skin feel comfortable. It is not a proven treatment for thinning.

What this calculator cannot tell you

It does the math only. It does not know which oil you are using, your allergies or your health. Patch test every new blend, keep it away from your eyes, and ask your doctor first if you are pregnant, breastfeeding, have a medical condition or want to use it on a child. If your scalp is sore, broken or shedding suddenly, skip essential oils and see a board-certified dermatologist.

Need the carrier side of the bottle? The hair oil blend builder picks base oils for your porosity, and the scalp massage timer walks you through applying it.

Essential oil dilution chart: drops per carrier amount

Carrier oil 0.5%1%2%3%
1 tablespoon (15 ml) 1 drop3 drops6 drops9 drops
1 fl oz (30 ml) 3 drops6 drops12 drops18 drops
2 fl oz (59 ml) 6 drops12 drops24 drops37 drops
100 ml 10 drops20 drops41 drops62 drops
4 fl oz (118 ml) 12 drops24 drops48 drops73 drops

Total drops of essential oil, assuming 20 drops per ml. Split the total evenly if you blend two or three oils.

Dilution levels

Dilution Typical use Drops per fl oz Drops per tablespoon
0.5% · Extra gentle Very reactive skin, or along the hairline and behind the ears 3 1
1% · Gentle Sensitive skin, or your first time with an oil 6 3
2% · Standard Leave-on scalp oil for most adults 12 6
3% · Strong Short-contact pre-wash oil that you shampoo out 18 9

Frequently asked questions

How many drops of essential oil per ounce of carrier oil?
At the usual 20 drops per ml, a 1% dilution is about 6 drops per fluid ounce of carrier oil, 2% is about 12 drops and 3% is about 18 drops. Your dropper may give more drops per ml, so treat these as estimates.

What essential oil dilution is safe for the scalp?
A 2% dilution is the common choice for a leave-on scalp oil for adults, and 1% is a better start for sensitive skin. Some oils have lower limits of their own, so check the label, patch test first, and stop if your scalp burns or itches.

Can I put rosemary or peppermint oil straight on my scalp?
No. Undiluted essential oils can irritate or sensitize the skin. Always mix them into a carrier oil such as jojoba, grapeseed or olive oil first.

Does rosemary oil or peppermint oil grow hair?
The evidence is thin. One small six-month trial in people with pattern hair loss reported more hair with rosemary oil, and it has not been repeated in large studies. The peppermint oil study was done on mice, which is not evidence in people. Neither oil is a proven treatment for hair loss.

Is it safe to use essential oils on my scalp while pregnant?
Ask your doctor first. The same goes for breastfeeding, any medical condition and any use on children. This calculator only does the dilution math.

Why does the number of drops change with the dropper?
A drop is not a fixed measure. Thin oils and narrow dropper tips give small drops, about 30 per ml, while thick oils and wide tips give about 20 per ml. The calculator assumes 20 and lets you change it.

How long does a diluted essential oil blend keep?
It keeps about as long as the carrier oil it is mixed into, usually several months in a dark bottle away from heat. Throw it out if it smells sharp, sour or like crayons. To choose a carrier, try the hair oil blend builder.

Sources

Last data update:

  1. Tisserand R, Young R. Essential Oil Safety: A Guide for Health Care Professionals. 2nd ed. Churchill Livingstone; 2014. Reference for essential-oil dilution limits, skin sensitization and use in pregnancy.
  2. Panahi Y, Taghizadeh M, Marzony ET, Sahebkar A. Rosemary oil vs minoxidil 2% for the treatment of androgenetic alopecia: a randomized comparative trial. Skinmed. 2015;13(1):15-21. Small 6-month trial in which rosemary oil and 2% minoxidil produced similar hair-count changes in androgenetic alopecia; not a large or replicated study.
  3. Oh JY, Park MA, Kim YC. Peppermint oil promotes hair growth without toxic signs. Toxicol Res. 2014;30(4):297-304. Animal (mouse) study of topical peppermint oil and hair growth — not evidence in humans.

How we research and update pages: editorial policy. Spotted an error? Tell us.

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