Table of Contents
- How Much Essential Oil to Add to Castile Soap
- Quick Chart: Best Essential Oils for Castile Soap
- The 10 Best Essential Oils for Castile Soap
- 1. Lavender (Lavandula angustifolia)
- 2. Sweet Orange (Citrus sinensis)
- 3. Roman Chamomile (Chamaemelum nobile)
- 4. Tea Tree (Melaleuca alternifolia)
- 5. Geranium (Pelargonium graveolens)
- 6. Frankincense (Boswellia carterii)
- 7. Lemongrass (Cymbopogon flexuosus)
- 8. Peppermint (Mentha × piperita)
- 9. Rosemary (Salvia rosmarinus, formerly Rosmarinus officinalis, ct. cineole)
- 10. Eucalyptus (Eucalyptus radiata or E. globulus)
- Castile Soap Blends to Try
- How to Choose the Right Oil
- FAQs
Updated November 2026
The best essential oils to mix with castile soap are lavender, sweet orange, Roman chamomile, tea tree, peppermint, eucalyptus, rosemary, lemongrass, geranium, and frankincense. For body products I use 10 to 15 drops per ½ cup of castile soap, which is 40 to 60 drops in a 16 oz bottle. Below is a quick chart, then a closer look at each oil: its scent, which soap it's best in, who it's right for, and what it blends with. Jump to the chart.
This guide is all about choosing your oils. For step-by-step recipes like hand soap, body wash, dish soap, and an all-purpose cleaner, see essential oils and castile soap recipes. To learn about the soap itself, read my guide to the benefits of castile soap.
How Much Essential Oil to Add to Castile Soap
Soap rinses off, so it needs less essential oil than a lotion or roller blend. I keep body products at about 1% or less. Always mix the oils into the soap before adding any water.
| Castile soap | Essential oil drops |
|---|---|
| ½ cup (4 oz) | 10 to 15 drops |
| 1 cup (8 oz) | 20 to 30 drops |
| 16 oz bottle | 40 to 60 drops |
For soap made just for kids 5 to 11, or for sensitive skin, use half the drops.
For household cleaners, I use 10 to 20 drops in a quart of diluted castile soap.
Quick Chart: Best Essential Oils for Castile Soap
| Essential oil | Scent | Best in | Ages |
|---|---|---|---|
| Lavender | Soft floral | Body wash, hand soap, bath | 2+ |
| Sweet orange | Sweet citrus | Hand soap, dish soap, cleaners | 2+ |
| Roman chamomile | Sweet, apple-like | Evening body wash, bath | 2+ |
| Frankincense | Warm, resinous | Evening body wash | 2+ |
| Tea tree | Fresh, earthy | Hand soap, cleaners | 5+ |
| Geranium | Rosy floral | Body wash, hand soap | 5+ |
| Peppermint | Cool mint | Morning body wash, foot soak | 6+ |
| Rosemary | Fresh herbal | Morning body wash, shampoo | 10+ |
| Eucalyptus | Clean, sharp | Shower soap, cleaners | 10+ |
| Lemongrass | Lemony, herbal | Kitchen hand soap, cleaners | Adults only on skin |
The 10 Best Essential Oils for Castile Soap
1. Lavender (Lavandula angustifolia)
If you only buy one oil for your castile soap, make it lavender. It's soft, floral, and calming, and gentle enough for the whole family. It's my go-to for an evening shower or a relaxing bath.
- Best in: body wash, hand soap, bath soak, shampoo
- Ages: 2+
- Blends well with: orange, Roman chamomile, geranium, frankincense, cedarwood
Learn more in my lavender essential oil uses guide.
2. Sweet Orange (Citrus sinensis)
Sweet orange smells cheerful and is easy on the budget. It brightens up a hand soap or dish soap and plays well with almost every other oil on this list. Unlike some citrus oils, sweet orange isn't sun-sensitive.
- Best in: hand soap, dish soap, all-purpose cleaner
- Ages: 2+
- Blends well with: lavender, peppermint, frankincense, lemongrass, cedarwood
More ideas are in my orange essential oil blends.
3. Roman Chamomile (Chamaemelum nobile)
Roman chamomile has a sweet, apple-like scent and is one of the gentlest oils I use. It's lovely in an evening body wash, and a favorite for little ones. It's pricier than most, so I often blend a few drops with lavender. Skip it with a ragweed or daisy allergy.
- Best in: evening body wash, bath soak
- Ages: 2+
- Blends well with: lavender, orange, geranium, frankincense
4. Tea Tree (Melaleuca alternifolia)
Tea tree has a fresh, earthy, slightly medicinal scent that I love in hand soap and household cleaners. It's strong, so I usually soften it with lemon, orange, or lavender. Use a fresh bottle, since old tea tree is more likely to irritate skin.
- Best in: hand soap, all-purpose cleaner, foot soak
- Ages: 5+
- Good to know: cats are especially sensitive to tea tree, so rinse surfaces well and keep pets out of the room while you clean
- Blends well with: lemon, orange, lavender, eucalyptus, peppermint
See my full tea tree essential oil guide and how to dilute tea tree oil.
5. Geranium (Pelargonium graveolens)
Geranium smells rosy and green, like a garden in bloom, at a much friendlier price than rose. It adds a pretty floral note to a body wash or a guest bathroom hand soap.
- Best in: body wash, hand soap
- Ages: 5+
- Blends well with: lavender, orange, frankincense, Roman chamomile
6. Frankincense (Boswellia carterii)
Frankincense has a warm, resinous, slightly citrusy scent that feels grounding. I love it in an evening body wash when I want to slow down. Look for Boswellia carterii on the label.
- Best in: evening body wash, bath soak
- Ages: 2+
- Blends well with: lavender, orange, geranium, cedarwood
7. Lemongrass (Cymbopogon flexuosus)
Lemongrass is bright, lemony, and herbal, and it's wonderful in a kitchen hand soap or cleaner. It's a strong skin sensitizer, so on skin it's for adults only and stays at the low end of the drop range. In cleaners for surfaces, it's fine to use more freely.
- Best in: kitchen hand soap, all-purpose cleaner
- Ages: adults only on skin
- Blends well with: orange, lavender, tea tree, peppermint
Find more ideas in my lemongrass essential oil guide.
8. Peppermint (Mentha × piperita)
Peppermint is cool and crisp, lovely for a wake-up shower or a tired-feet soak. It tingles on the skin, so a little goes a long way. Keep it away from your face and eyes.
- Best in: morning body wash, foot soak
- Ages: 6+
- Blends well with: orange, grapefruit, rosemary, eucalyptus, lavender
More in my peppermint essential oil uses post.
9. Rosemary (Salvia rosmarinus, formerly Rosmarinus officinalis, ct. cineole)
Rosemary is fresh, herbal, and energizing. I like it in a morning body wash with citrus, and in a simple castile shampoo.
- Best in: morning body wash, shampoo
- Ages: 10+
- Blends well with: grapefruit, orange, peppermint, lavender
10. Eucalyptus (Eucalyptus radiata or E. globulus)
Eucalyptus has a clean, sharp scent that feels like a spa shower. I use it in shower soap and in household cleaners.
- Best in: shower soap, all-purpose cleaner
- Ages: 10+
- Blends well with: peppermint, lavender, tea tree, lemon
Castile Soap Blends to Try
Each blend below is for ½ cup of unscented castile soap. Stir the oils into the soap, then use it as is or follow any recipe in my castile soap recipes.
| Blend | Use | Ages |
|---|---|---|
| Relaxing Evening Blend | Body wash | 5+ |
| Fresh Kitchen Hand Soap Blend | Hand soap | 5+ |
| Rosy Garden Blend | Body wash | 5+ |
| Energizing Morning Blend | Body wash | 10+ |
Relaxing Evening Blend
Body wash · Ages 5+ · 13 drops in ½ cup
A soft, sweet floral for an evening shower or bath.
- 6 drops lavender (Lavandula angustifolia)
- 4 drops Roman chamomile (Chamaemelum nobile)
- 3 drops ylang ylang (Cananga odorata)
- ½ cup unscented castile soap
Fresh Kitchen Hand Soap Blend
Hand soap · Ages 5+ · 12 drops in ½ cup
Bright orange with a clean tea tree edge for the kitchen sink.
- 8 drops sweet orange (Citrus sinensis)
- 4 drops tea tree (Melaleuca alternifolia)
- ½ cup unscented castile soap
Rosy Garden Blend
Body wash · Ages 5+ · 13 drops in ½ cup
Rosy geranium, soft lavender, and warm frankincense.
- 6 drops geranium (Pelargonium graveolens)
- 4 drops lavender (Lavandula angustifolia)
- 3 drops frankincense (Boswellia carterii)
- ½ cup unscented castile soap
Energizing Morning Blend
Body wash · Ages 10+ · 15 drops in ½ cup
Cool mint, bright orange, and fresh eucalyptus for a wake-up shower.
- 5 drops sweet orange (Citrus sinensis)
- 5 drops peppermint (Mentha × piperita)
- 5 drops eucalyptus (Eucalyptus radiata)
- ½ cup unscented castile soap
Note: Keep this one away from your face and eyes.
How to Choose the Right Oil
- For kids: stick with lavender, sweet orange, Roman chamomile, or frankincense (ages 2+), and add geranium or tea tree from age 5. Use half the adult drops in soap made just for them.
- For sensitive skin: choose lavender or Roman chamomile, use the low end of the range, and patch test first.
- For a morning boost: try peppermint, rosemary, or citrus.
- For winding down: try lavender, Roman chamomile, or frankincense.
- For cleaning: tea tree, orange, lemongrass, and eucalyptus are my favorites.
A Few Safety Basics
• Keep essential oils away from babies under 2. With a baby in the house, use unscented soap for them.
• Keep body products at about 1% or less, and patch test a new oil on your inner forearm for 24 to 48 hours.
• Check the age on each oil and blend. Kids 2 to 4 use only six starter oils, after checking with your pediatrician.
• Keep soap away from your eyes, and rinse with plenty of water if it gets in.
• If you're pregnant, check with your doctor or midwife first. Shower and bath products with essential oils wait until after the first 16 weeks.
• Don't premix castile soap with Epsom salt or vinegar. For a bath, pour the soap and oil mix into the water first, then add the salt.
• Never put oils on pets, and diffuse with a door open so they can leave. Cats are especially sensitive, including to tea tree, citrus, peppermint, eucalyptus, pine, wintergreen, cinnamon, clove, and ylang ylang.
• Never swallow essential oils, and store soaps and oils out of reach of children and pets. If someone swallows an oil, call Poison Control at 1-800-222-1222.
More Castile Soap Posts
- Essential Oils and Castile Soap: Easy DIY Recipes
- Benefits of Castile Soap: What It Is and How to Use It
- Natural Foaming Body Wash Recipes
- 20 Essential Oil Cleaning Recipes
Ready to make your own? My Aromatherapy Supply Kits have the bottles and supplies you need, and my free essential oil guides are full of blend ideas.
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