How to Make an Essential Oil Blend: 30/50/20 Rule & Ratios Guide Australia
What Is an Essential Oil Blend and How Does It Work?
An essential oil blend is a mix of two or more essential oils combined in set proportions to create one balanced aroma that no single oil can produce on its own. Each oil evaporates at a different speed, so a well-built blend opens with bright notes, settles into a fuller heart and finishes with a deeper, lingering base.
- Top notes are the lightest oils. They reach your nose first and fade fastest, usually citrus and mint oils.
- Middle notes form the heart of the blend. Floral and herbal oils such as lavender and geranium sit here.
- Base notes are the heaviest oils. Woods and resins such as cedarwood and patchouli anchor the aroma and help it linger.
Blending lets you shape the mood of a room rather than relying on one scent. If you would rather start from ready-made options, browse our diffuser oils collection, shipped from Australia by an Australian essential oil business.
What Is the 30/50/20 Rule for Essential Oil Blends?
The 30/50/20 rule for essential oil blends means 30% top notes, 50% middle notes and 20% base notes, which gives a balanced aroma that opens brightly and lasts. You will also see it written as the 20/30/50 rule. It is the same idea in a different order, and some makers push the base closer to 30% when they want a heavier, longer-lasting blend.
| Note | Share of Blend | 10-Drop Batch | 20-Drop Batch | Example Oils |
|---|---|---|---|---|
| Top | 30% | 3 drops | 6 drops | Sweet Orange, Bergamot, Lemon, Grapefruit, Peppermint |
| Middle | 50% | 5 drops | 10 drops | Lavender, Geranium, Rosemary, Clary Sage, Roman Chamomile |
| Base | 20% | 2 drops | 4 drops | Cedarwood, Patchouli, Vetiver, Sandalwood, Frankincense |
Treat the rule as a starting point, not a law. Strong oils can throw the ratio off, so adjust by smell after your first test batch.
How Do You Make an Essential Oil Blend at Home?
You make an essential oil blend at home by choosing one top, one middle and one base oil, adding them drop by drop in a 30/50/20 ratio, then letting the mix rest before use. A 10-drop test batch keeps waste low while you learn how each oil behaves.
- Step 1: Pick a mood, such as fresh and bright or soft and woody, then choose one oil from each note group.
- Step 2: Add 3 drops of the top note, 5 drops of the middle note and 2 drops of the base note to a clean amber glass bottle, then swirl gently.
- Step 3: Cap the bottle, label it and let it rest for 24 to 48 hours so the aroma can settle before you judge it.
A simple evening example uses 3 drops of Sweet Orange, 5 drops of Lavender and 2 drops of Cedarwood. Sweet orange oil (Citrus sinensis, family Rutaceae) is cold-pressed from the fruit peel and is rich in d-limonene, typically above 90%, which gives the blend its bright opening. Lavender essential oil (Lavandula angustifolia, family Lamiaceae) is steam distilled from the flowering tops, with linalool and linalyl acetate as its main constituents. Himalayan cedarwood (Cedrus deodara, family Pinaceae) is steam distilled from the wood and carries the dry, woody finish.
For the diffuser, add 3 to 5 drops of your finished blend per 100 mL of water. Our guide to essential oils for diffusers covers tank sizes, run times and more recipes. Prefer a ready-made starting point? Sweet Dreams and Stress Relief are pre-balanced 10 mL blends you can diffuse straight from the bottle.
What Are the Best Essential Oil Combinations by Scent Family?
The best essential oil combinations by scent family pair citrus with florals or woods, and herbal oils with spice or woods, because these families share enough character to blend smoothly. Start with two oils at a 2:1 ratio, then add a third once the pair smells right.
- Citrus and floral: Lavender and Bergamot at 2:1 gives a soft floral scent with a bright citrus lift.
- Citrus and woody: Sweet Orange and Cedarwood at 2:1 gives a juicy, warm aroma with a dry, grounded finish.
- Herbal and woody: Rosemary with Cedarwood or Vetiver gives a clean, green aroma with depth.
- Floral and resinous: Geranium with Frankincense gives a rosy, rounded scent with a soft resin base.
- Spice and citrus: A small amount of spice oil, such as clove or cinnamon, lifted by orange or lemon gives a warm, cosy blend.
If you enjoy warm, spicy aromas but want a finished blend, Five Thieves is a ready-made 10 mL option for the diffuser.
Which Essential Oil Combinations Clash in a Blend?
Essential oil combinations clash when several dominant oils, such as clove, peppermint and patchouli, are used in equal amounts, because each one competes to lead the aroma. The result is a muddy, heavy scent where no single note comes through clearly.
Keep strong oils to one or two drops per 10-drop batch and let lighter oils carry the volume. For skin blends, avoid stacking several oils known for skin sensitivity, such as cinnamon bark, clove, oregano and thyme, in one mix. Three to five oils is plenty for most blends; more than that rarely improves the result.
What Makes an Essential Oil Blend Scent Last Longer?
An essential oil blend scent lasts longer when it contains enough base notes, such as sandalwood, patchouli, vetiver or cedarwood, because these heavier oils evaporate slowly and hold the lighter notes in place. Citrus and mint oils fade quickly on their own, so a blend built only from top notes disappears fast.
- Raise the base note from 20% towards 30% for a longer-lasting blend.
- Let the finished blend rest for 24 to 48 hours before use.
- Store blends in amber glass with a tight cap, away from heat and direct sunlight.
How Do You Dilute an Essential Oil Blend for Skin?
You dilute an essential oil blend for skin by mixing it into a carrier oil at 1% to 3%, which is 2 to 6 drops of blend per 10 mL of carrier. Never apply an essential oil blend undiluted, and always patch test on the inner arm 24 hours before wider use.
- 1% (2 drops per 10 mL): Suitable for the face and sensitive skin.
- 2% (4 drops per 10 mL): A general everyday strength for body and massage blends.
- 3% (6 drops per 10 mL): For short-term use on a small area only.
A light, non-greasy carrier such as Fractionated Coconut Oil works well for roll-on and massage blends. Some cold-pressed citrus oils, including bergamot, can increase sensitivity to sunlight, so avoid sun exposure on treated skin for 12 hours.
Essential oils are for external use only and must never be swallowed. If you are pregnant or breastfeeding, seek advice from a qualified healthcare professional before use, and keep blends out of reach of children and pets. Diffuse in a well-ventilated room and give pets a way to leave the space. In case of accidental ingestion, contact the Poisons Information Centre on 13 11 26.
Once you understand notes, ratios and dilution, making your own essential oil blend becomes simple and repeatable. Start with a 10-drop test batch, write down what you used, and adjust one drop at a time until the aroma suits your space.
Disclaimer: This article is for general information only and is not medical advice. purelyBlack essential oils are not intended to diagnose, treat, cure or prevent any disease. Always read the label, use as directed, and consult a qualified healthcare professional if you have a medical condition, are pregnant or breastfeeding, or are using oils around children or pets.
About the Author
H.R. Kim is the Fragrance Editor at purelyBlack, a Sydney-based, Australian-owned botanical perfumery and essential oil business. She writes practical guides on blending, aroma and safe everyday use of 100% pure essential oils for Australian homes.
Last Updated: September 2026
