How to Use IFRA Math
Fragrance Safety & Compliance Calculator
IFRA Math helps you check whether your fragrance blend is safe to use in a specific product type. It calculates the maximum usage rate for your blend based on IFRA (International Fragrance Association) standards, identifies restricted components in your essential oils, and flags EU allergens that may require label declaration. Whether you're making soap, lotion, perfume, or candles, IFRA Math ensures your fragrance levels stay within safe limits.
What Is IFRA?
The International Fragrance Association (IFRA) is the global representative body of the fragrance industry. IFRA publishes safety standards that set maximum usage levels for fragrance ingredients based on scientific research and safety data. These standards are organized by product category — different product types have different limits because of how they contact the skin.
For example, a leave-on face cream (Category 5B) has stricter limits than a rinse-off bar soap (Category 9) because face cream stays on the skin longer and contacts a more sensitive area. IFRA standards help formulators make products that are safe for consumers while still smelling great.
How to Use IFRA Math
Follow these steps to check your fragrance blend against IFRA safety limits.
- Step 1: Search for an essential oil or fragrance material in the oil library and add it to your blend.
- Step 2: Set the percentage of each oil in your fragrance blend (all oils should total 100%).
- Step 3: Review and adjust the chemical components listed for each oil. You can edit concentrations or add missing components.
- Step 4: Click "Calculate Compliance" to generate your IFRA results report.
- Step 5: Review the results — the report shows maximum usage rates for every IFRA category, component breakdowns, and EU allergen declarations.
Example: You're blending lavender (70%) and tea tree (30%) for a body lotion. Add both oils, set their percentages, and calculate. The report will show that for Category 5A (body creams), your maximum fragrance usage rate might be 4.2%, meaning your finished lotion should contain no more than 4.2% of this blend.
Understanding IFRA Categories
IFRA groups products into categories based on exposure type and skin contact area. Here are the main categories:
Category 1 — Lip Products & Toys
Products applied to or near the lips and children's toys. Strictest limits due to potential ingestion.
Category 2 — Deodorants & Body Sprays
Products applied to underarms and body. Relatively strict limits due to prolonged skin contact on sensitive areas.
Category 3 — Eye & Facial Makeup
Eye products, makeup, and facial treatment masks. Strict limits due to contact with delicate facial skin.
Category 4 — Perfume & Fine Fragrance
Perfume, cologne, solid perfume, and fragranced bracelets. Applied directly to skin in concentrated form.
Categories 5A–5D — Leave-On Body, Face, Hand & Baby
Body creams (5A), face creams and beard oils (5B), hand creams (5C), and baby products (5D). Limits vary by body area and user sensitivity.
Category 6 — Oral Care
Mouthwash, toothpaste, and breath sprays. Very strict limits due to oral exposure.
Categories 7A–7B — Hair Products
Rinse-off hair treatments (7A) and leave-on hair treatments (7B). Leave-on products have stricter limits.
Category 8 — Wipes
Intimate wipes and baby wipes. Moderate limits for brief skin contact products.
Category 9 — Rinse-Off Products
Bar soap, liquid soap, shampoo, and shower gel. More relaxed limits because the product washes off quickly.
Categories 10A–10B — Household & Air Care
Cleaning products and reed diffusers (10A), air freshener sprays (10B). Different exposure profiles than skin contact products.
Categories 11–12 — Non-Skin Contact
Diapers and scented clothing (11A–11B), candles, incense, and air fresheners (12). Generally more relaxed limits.
Common Use Cases
Tips for Fragrance Safety
- Always patch test new fragrances on a small area of skin before using them in products, even if they meet IFRA limits.
- Check for EU allergens in your blend and declare them on product labels when required. This protects consumers with known sensitivities.
- Use proper dilution rates — essential oils should never be applied undiluted to skin. IFRA limits refer to the concentration in the finished product.
- Request IFRA certificates from fragrance oil suppliers to verify their safety data matches what you're calculating.
- When in doubt, use lower fragrance percentages. Staying well below the maximum limit provides an extra margin of safety.