Essential oil dilution chart and calculator
Enter how much carrier oil you have and who the blend is for, and see how many drops of essential oil to add, split between up to three oils.
| Carrier oil | 30 ml |
|---|---|
| Strength | 2% |
| Essential oil in total | 12 drops (exactly 12, rounded down) |
| Lavender | 8 drops |
| Cedarwood | 4 drops |
| Note | Body oils, massage blends, after-bath oil. |
| Carrier | 0.5% | 1% | 2% | 3% | 5% |
|---|---|---|---|---|---|
| 5 ml | 0 | 1 | 2 | 3 | 5 |
| 10 ml | 1 | 2 | 4 | 6 | 10 |
| 15 ml | 1 | 3 | 6 | 9 | 15 |
| 30 ml | 3 | 6 | 12 | 18 | 30 |
| 50 ml | 5 | 10 | 20 | 30 | 50 |
| 100 ml | 10 | 20 | 40 | 60 | 100 |
How to use it
- Enter the amount of carrier oil, in milliliters, teaspoons, tablespoons or US fluid ounces.
- Choose who the blend is for from the list below, or type your own percentage.
- Add up to three essential oils and the parts for each, such as 2 : 1 or 1 : 1 : 1.
You get the total number of drops and the drops for each oil. If the batch is too small for even one drop, the calculator tells you how much carrier you would need instead. The print button prints your result together with the chart, which is handy to keep in the cupboard with your bottles.
| Who or where | Strength |
|---|---|
| Adult body, used most days | 2% |
| Adult face | 1% |
| Adult, small area for a few days | 3% |
| Sensitive skin | 0.5% |
| Older adults | 1% |
| Pregnancy, after asking a midwife or doctor | 1% |
| Children 6 to 12 | 1% |
| Children 2 to 6 | 0.5% |
These are the same levels used across the site's aromatherapy pages, from face oils to blends for children.
How the numbers work
A dilution percentage is the share of the finished blend that is essential oil. The calculator turns it into drops with one rule: milliliters of carrier, multiplied by 20 drops per milliliter, multiplied by the percentage, divided by 100. So 10 ml at 1% is 10 times 20 times 1, divided by 100, which is 2 drops.
Twenty drops per milliliter is a convention rather than a measurement. Real drops vary with how thick the oil is and with the dropper insert in the bottle neck, from roughly 15 to 40 drops per milliliter. Because of that uncertainty, the answer is always rounded down, never up, so a blend can come out slightly weaker than planned but never stronger.
Spoons and ounces are converted to milliliters first: 1 teaspoon is 4.93 ml, 1 tablespoon is 14.79 ml and 1 US fluid ounce is 29.57 ml.
When the result is under one drop, the calculator does not round up to a drop that would overshoot. It suggests a bigger batch: one drop at 0.5% needs 10 ml of carrier.
The chart below the tool covers 5, 10, 15, 30, 50 and 100 ml at 0.5%, 1%, 2%, 3% and 5%. The 5% column is there so you can recognize how strong a recipe is. It is meant for very short use on a small area, which is why it is not offered as a preset.
When you split a blend by parts, the drops for each oil always add up to the total. If the total does not divide evenly, the leftover drop goes to the oil whose share was closest to the next whole drop. The guide to blending factors helps you decide the parts so a strong oil does not drown out a gentle one.
A worked example
You want 30 ml of body oil for everyday use, so you choose "adult body" at 2%. That is 30 times 20 times 2, divided by 100: 12 drops in total. With lavender and cedarwood at 2 : 1, the calculator gives 8 drops of lavender and 4 of cedarwood.
Now say your bottle is sold as 1 US fluid ounce. That is 29.6 ml, and at 2% the math gives 11.8 drops. The calculator shows 11, not 12. With the same 2 : 1 split, that becomes 7 drops of lavender and 4 of cedarwood.
Some oils have a much lower maximum on skin than your general strength: cinnamon bark, clove, lemongrass and cold-pressed bergamot among them. For those, the general percentage sets the total, and the oil's own ceiling caps its share. The ceilings for each of them, with worked drop counts, are in our dilution chart for skin.
What it can't tell you
The calculator does arithmetic. It cannot tell whether an oil suits you, whether it has gone stale, or whether a group should avoid it altogether. Check each oil in the essential oil safety chart before you blend.
- Babies under 3 months: no essential oils at all. The presets stop at age 2, so for a younger child ask a doctor or pharmacist first.
- Pregnancy and breastfeeding: talk to a midwife or doctor first, especially in the first three months.
- Regular medicines, epilepsy or asthma: ask a doctor or pharmacist before using oils on skin or in the air.
- Patch test every new blend at the strength you plan to use, on a small area of the inner forearm, and wait at least a day.
- Keep blends away from the eyes and off broken or inflamed skin, and never swallow essential oils.
Stop using a blend if your skin turns red, itchy or bumpy. See a doctor or pharmacist if a rash spreads, blisters or has not settled after a few days. Swelling of the lips, tongue or throat, or trouble breathing, needs emergency care straight away.
Questions
How do you dilute essential oils for skin?
Measure the carrier oil into a clean glass bottle, work out the drops for the strength you want (2% for an adult body oil, 1% for the face), add them, cap the bottle and roll it gently. Label it with the oils, the percentage and the date.
How many drops of essential oil go in 1 oz of carrier oil?
For 1 US fluid ounce (29.57 ml), the calculator gives 5 drops at 1% and 11 drops at 2%.
How do you blend essential oils?
Decide the total drops first, then share them out by parts. A 2 : 1 blend of 12 drops is 8 and 4. The total stays the same however many oils you use.
Is 5% dilution safe?
Only for a short time on a small area. For anything used daily or over large areas of skin, stay at 2% or below.
What if my blend needs less than one drop?
Make a bigger batch. One drop at 0.5% needs 10 ml of carrier, and one drop at 1% needs 5 ml.
Sources
- Robert Tisserand and Rodney Young, Essential Oil Safety, 2nd edition: dilution levels and maximum skin levels for single oils.
- NAHA, the US aromatherapy association: safety guidance on dilution.
- The NHS on patch testing before using a new product on skin.