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Essential Oils Dilution Guide

N-ESSENTIALS PRACTICAL GUIDE
Essential Oils Dilution Guide
Practical dilution ranges, calculations and safety guidance

Scientifically reviewed and endorsed by: Jacinta Meyers, Principal Scientist, The F.A.C.T.S. Group
Written by: Kacie La, Founder, N-Essentials
31 August 2026 | 6 minute read
BEFORE YOU BEGIN
Essential oils are highly concentrated substances. Before putting them on your skin, mix them into a carrier oil, balm, cream or another properly formulated base. Dilution helps reduce the chance of irritation, burning and allergic reactions due to unsafe exposure.
For adult leave-on products, up to 0.5% is a reasonable starting point for the face and up to 1.5% for the body. These are starting points. Not safe limits. Some essential oils need less.
What does “dilution” mean?
A 1% dilution means the final product contains:
•1% essential oil
•99% carrier oil or other suitable base
If more than one essential oil is used, the percentage applies to all the essential oils together.
For example, a 30 mL body oil at 2% contains 2% of essential oil total. Not 2% of each oil.
Which dilution should I use?
Essential Oil Dilution
Suitable starting point
Up to 0.3%
Specialised products intended for use near, but not in, the eye area. Only use essential oils specifically assessed as suitable for that application.
Up to 0.5%
Facial products, sensitive adult skin or first-time use
Up to 1.5%
Everyday adult body products and products applied over larger areas
Up to 1.8%
Adult wash off products
Up to 3%
More concentrated short-term adult use on a small area. Only if the irritancy profiles of the selected oils allow it.
Above 3%
Needs specific safety information and is not recommended as a general DIY starting point unless the essential oil blend is to be used for inhalation only e.g., pure essential oil blends for use in diffusers.
Always choose the lower percentage of:
•The dilution suggested for the intended use; and
•The maximum permitted amount for the individual essential oil.
How to calculate dilution by weight
When determining the amounts of essential oils to use, best practice is to weigh all ingredients. Use a scale that is accurate to at least 0.01g. Use this formula:
DILUTION FORMULA
Essential oil required = total batch weight × dilution percentage ÷ 100
Example: 30 g facial oil at 0.5%
•Essential oil: 30 × 0.5 ÷ 100 = 0.15 g
•Carrier oil: 30g - 0.15g = 29.85g
If using two or more essential oils, their total weight should still be 0.15 g.
How to make a diluted essential oil blend
•Decide where and how often the product will be used.
•Check the safety information for each oil.
•Choose the lowest suitable dilution.
•Measure the essential oils and carrier separately.
•Mix them together thoroughly.
•Label the container with the ingredients, dilution percentage and date made.
•Test an amount of the finished blend on a small area of skin such as the inside of your arm, and evaluate for 24 hours.
A small skin test cannot guarantee that a reaction will not happen. Stop using the product if you notice burning, redness, itching, swelling, or a rash.
Choosing a suitable base
For facial and body oils
Suitable carrier oils may include:
•Jojoba oil
•Sweet almond oil
•Fractionated coconut oil
•Grapeseed oil
•Apricot kernel oil
•Macadamia oil
Think about skin type, allergies, texture, and how long the product will last when choosing a carrier.
For balms and body butters
Calculate the essential oil percentage using the weight of the whole finished batch including oils, butters and waxes. Add essential oils during the cool-down stage so they are not exposed to high heat.
For creams and lotions
Follow a tested recipe. Essential oils should normally be added during the cool-down stage and included in the total formula percentage.
For water-based products
Essential oils do not dissolve in water. A spray, toner or gel generally requires:
•A suitable solubiliser or emulsifier
•A suitable preservative system
•A tested formulation
Including instructions to shake the bottle does not create a stable or reliable, safe product.
For baths
Do not add undiluted essential oils directly to bath water. Water, epsom salts and milk do not safely spread oils, which may stay concentrated on the surface and touch the skin. Use a ready-made bath base or suitable dispersant. Avoid using peppermint oil in bath or body wash products. The menthol can create a burning sensation when magnified by warm bath water and open pores. Contact with sensitive areas of the body may lead to severe discomfort.
Important safety limits
Oil-specific maximums
Some oils can cause irritation or allergic reactions at amounts much lower than the general percentages in this guide. For example, clove oil has a recommended maximum dermal limit of 0.5%. Always check the supplier’s product-safety information.
Sunlight and citrus oils
Some cold-pressed citrus oils - including some types of bergamot, lemon, grapefruit and bitter orange, can cause a reaction when skin is exposed to sunlight or other ultraviolet light after application. Some distilled or furocoumarin-free versions may not cause phototoxic reactions. Testing needs to be performed on each batch of oil to confirm if it is photosensitising. Check with your essential oil supplier if you are unsure.
When selecting essential oils for use in cosmetic products where skin exposure to the sun is likely after using the product, check the method of extraction e.g., cold pressed or steam distilled, and the oil-specific maximum dermal application limit, taking into account all of the known allergens present in your essential oil or essential oil blend. If unsure, avoid applying the product to skin that will be exposed to Ultraviolet light. A reaction may happen after applying a photosensitising oil to the skin up to 12 hours after (or even longer), if the skin is exposed to UV light.
Further reading: Phototoxicity guidance
Children and higher-risk users
A general adult dilution chart should not be used automatically for:
•Babies or children
•Pregnant or breastfeeding people
•Older adults, frail people, or people with significant health conditions
•People with asthma, epilepsy or significant allergies
•People with damaged or very sensitive skin
•People taking medicines that may interact with oils
•Pets
Some oils should be avoided completely for certain age groups or health conditions. Get advice from a suitably trained health professional or qualified aromatherapy practitioner.
Essential oil safety checklist
•Always store essential oils in glass containers, preferably amber, not clear glass.
•Do not put undiluted essential oils on the skin.
•Do not use near the eyes inside the ears or on mucous membranes.
•Do not use on skin that is cut, damaged or very irritated.
•Do not swallow essential oils.
•Keep bottles closed, away from heat and sunlight.
•Keep all essential oils out of reach of children and pets.
•Do not think that "natural" means safe.
•Safely dispose of oils that smell different from when they were first opened, look old or have been stored badly.
When making products for sale that contain essential oils, check the product-category limits in the official IFRA Standards Library. Also check the IFRA Standards Library and SUSMP, the Australian Poisons Standard to see if any limits apply to the ingredients in each essential oil (search by the CAS number of each constituent). A general dilution chart is not a substitute for a product safety evaluation. All Cosmetic products must be safe for use as intended. This includes stability and other laboratory tests.
If accidental exposure occurs
If an essential oil is swallowed, gets into the eyes, or causes a significant reaction, call the Australian Poisons Information Centre immediately on 13 11 26. It operates 24 hours a day. Do not wait for symptoms to appear. For a life-threatening emergencies, call 000.
This guide provides general educational information for cosmetic DIY use. It does not replace product-specific safety instructions, professional medical advice, or a formal safety assessment.
First Published: 1 September 2026 | Last Updated: 16 September 2026