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Fragrance & allergen check

Your fragrance load as a percentage of oils and of the finished product, checked against the certificate maximum for the right IFRA category — and what your supplier's allergen declaration comes to on the label. Nothing here invents a limit: it works from your supplier’s documents or, for an essential oil, from the IFRA Standards.

What are you making
IFRA category 9 · rinse-off. Bar and liquid soap, shampoo and bath bombs all sit in category 9; lotion is 5A, lip balm 1, candles 12.
Take both from your recipe. The lye calculator prints them.
A bar made at a 33 % lye solution loses about 6–10 % in four to eight weeks; only full-water recipes lose 10–15 %. It concentrates the allergens in the bar you actually sell.
Fragrances

add a fragrance

Calculated at soapformulator.com, every value sourced. Check the figures against your own scale.

The formula, and where it comes from 
Load, both ways
  f (g)      = oils × p ÷ 100                       # p = % of oils, the PPO habit
  f (g)      = base × p ÷ (100 − p)                 # p = % of finished product
  % of oils  = f ÷ oils × 100
  % of batch = f ÷ (base + f) × 100                 # what every limit is measured against

IFRA
  % as sold  = % of batch ÷ (1 − cure loss)          # the bar weighs less once cured; the scent stays
  % as sold ≤ the certificate maximum for the product's category
  blends (conservative): Σ (loadᵢ ÷ maxᵢ) ≤ 1

Allergens
  C_j = Σ_i (d_i × a_ij ÷ 100) ÷ (1 − cure loss)
        d_i = fragrance i as % of product
        a_ij = allergen j as % of fragrance i, from the supplier declaration
  declare if C_j > 0.001 % leave-on, > 0.01 % rinse-off

The dates that matter

European Union. Regulation (EU) 2023/1545 grew the list of fragrance allergens that must be named on a label from 24 entries to 81. You will also see it quoted as 26 growing to 82: that counts allergens rather than label entries, and includes two of the original 26, Hydroxyisohexyl 3-Cyclohexene Carboxaldehyde and Butylphenyl Methylpropional, which have since been prohibited outright. Products newly placed on the market must comply from 1 August 2026; everything on sale must comply from 1 August 2028. The thresholds themselves are unchanged: 0.001 % in a leave-on product, 0.01 % in a rinse-off one.

Great Britain has not adopted the expansion and still works to the original list, 24 entries now that two are prohibited. Northern Ireland follows the EU. If you sell to both, you need two label versions.

Canada phases in its own list: 24 allergens on all cosmetics from 12 April 2026, and the EU's expanded list on new products from 1 August 2026 and on everything by 1 August 2028.

IFRA is on its 51st Amendment. A 52nd was consulted on through June 2026 and is expected to be notified around January 2027, with eleven months for new creations and thirty for existing ones.

Every date, with the law it comes from, is in the regulatory calendar, which your calendar app can subscribe to.

Which category is my product

Bar soap, liquid soap, body wash, shampoo, rinse-off conditioner, bath bombs and anything else added to bathwater are all category 9. Body lotion is 5A, face moisturiser and beard oil 5B, hand cream 5C, baby products 5D. Lip balm is category 1, which carries the lowest limits of all. Deodorant is 2, solid perfume 4, leave-in hair products 7B. Candles and wax melts are 12; a room or linen spray is 10B, and a reed diffuser 10A. Where a product could be two things, the stricter category applies.

What this does not do

It does not know what is in your fragrance. For an essential oil it works from the typical composition IFRA publishes, and a certificate for your own lot comes first when it says otherwise. For a fragrance oil every limit comes from your supplier and belongs in your Product Information File. With an account, the fragrance library reads the maxima off a supplier’s certificate PDF, and the dossier puts it all together for your assessor.

Common questions

Why does my 6 % fragrance show as 3.8 %?

Because those are two different percentages of two different things. Soapmakers dose fragrance per weight of oils, which is what "6 % PPO" means. Every regulatory limit is a percentage of the finished product — oils plus lye plus water plus everything else. In a typical bar recipe a 6 % load on the oils is about 3.8 % of the batch. Quoting the wrong one against a certificate is the most common compliance mistake in this craft, so this page shows both and checks the limit against the right one.

Where do I get the maximum for my fragrance?

From your supplier. They issue a Certificate of Conformity for each fragrance, listing a maximum percentage for each of the twelve IFRA product categories. It is usually in the documents tab of the product page. IFRA itself issues no certificates and authorises nobody to certify on its behalf, so a supplier who cannot produce one has not got one. For the essential oils in the list, this page also works out a maximum from the IFRA Standards and the typical composition IFRA publishes for each oil. Natural oils vary from lot to lot, so a certificate for your own lot comes first.

What about a blend of two fragrances?

Certificates do not disclose which restricted materials are inside each fragrance, so the per-material sum the guidance describes is impossible for a maker to do. The conservative substitute, which this page uses, is that each fragrance uses up a share of its own allowance and the shares must not add past 100 %. Two fragrances each at half their own maximum are at the limit together.

Which allergens am I being asked about?

The ones your supplier declares. An allergen declaration is a separate document from the IFRA certificate: it lists each regulated fragrance allergen and its percentage in the fragrance compound. Paste that list and this works out what each one comes to in your finished product. The European list grew from 24 entries to 81 under Regulation (EU) 2023/1545 (you may see 26 and 82, which count the allergens differently), which applies to products newly placed on the market from 1 August 2026 and to everything from 1 August 2028. Great Britain has not adopted the expansion and still uses the original list, now 24 entries.

Why does cure weight loss matter?

A cold-process bar loses water during cure, which concentrates everything left behind. Classic Bells estimates that after four to eight weeks a bar still holds 50 to 70 % of the water it started with: for a bar made at a 33 % lye solution, about a fifth water when cut, that is about 6–10 % of its weight. Only full-water recipes lose 10–15 %. An allergen at 0.00095 % in the wet batch is over the 0.001 % leave-on threshold once the bar has lost 6 %. The conservative reading, and the one an assessor expects, is the as-sold weight.

Is this a compliance document?

No. It is arithmetic on numbers you supply from your own supplier documents. IFRA standards are voluntary and responsibility for a finished product rests with whoever makes it; an allergen declaration on a label has to be signed off by your Responsible Person or safety assessor. Use this to find problems early, not to prove you do not have any.

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