IFRA Category 4: how to read and calculate limits correctly

When a technical document states, for example, “IFRA Category 4: max 2.4%”, the first question should not be: “Can I put 2.4% of this raw material in my fragrance concentrate?” IFRA data must be read in the correct context because the Category 4 limit refers to the finished consumer product, not automatically to the fragrance concentrate prepared by the perfumer in the laboratory.

Confusing these two levels can lead either to unnecessarily restricted formulas or, in the opposite direction, to a finished product that does not comply. Here is how to read and calculate an IFRA Category 4 limit correctly.

What is IFRA Category 4?

According to IFRA Guidance, Category 4 includes fine-fragrance products generally applied to the neck, face and wrists: hydroalcoholic and non-hydroalcoholic fine fragrances of different types, including Eau de Toilette, Parfum, Cologne, solid perfume and fragrancing cream, as well as the aftershave products covered by this category.

The category therefore depends on the intended end use and exposure scenario, not simply on the commercial description “EDT”, “EDP” or “Extrait”. A perfume containing 15% fragrance concentrate and one containing 25% can both belong to Category 4; what changes is the calculation of the amount of each raw material in the finished product.

To confirm the appropriate category for a product, always consult the current IFRA Guidance and Standards.

The key point: the limit is in the finished product

IFRA Standards express the maximum acceptable concentration in the finished product for the relevant application category.

If a raw material has a Category 4 limit of 2.4%, the relevant amount of that material in the finished perfume must therefore not exceed 2.4%, according to the applicable document and Standard.

This value does not automatically mean 2.4% in the fragrance concentrate.

How to calculate from concentrate to finished product

The basic calculation is simple:

% raw material in finished product = % raw material in fragrance concentrate × fraction of fragrance concentrate in finished product

For example, if a raw material is present at 3% in the fragrance concentrate and the finished perfume contains 20% fragrance concentrate:

3% × 0.20 = 0.60%

The raw material is therefore present at 0.60% in the finished product.

The same principle applies to any concentration, provided the values are expressed on the same calculation basis. For regulatory work, weight/weight and volume/volume percentages should not be mixed arbitrarily.

The reverse calculation: how much can be used in the concentrate?

If you know the IFRA limit in the finished product and have already decided the concentration of your perfume, you can calculate the theoretical maximum in the fragrance concentrate:

theoretical maximum % in concentrate = IFRA limit in finished product ÷ fraction of concentrate in finished product

As an example, take TRIMOFIX / FIXAMBER, whose product information states IFRA Category 4: max 2.4% in the finished product.

This shows why the same IFRA limit produces different values in the concentrate. In a perfume containing 20% fragrance concentrate, for example, 12% of the raw material in the concentrate corresponds to 2.4% in the finished product.

Important: these are theoretical mathematical maxima, not recommended dosages. They are valid only if the limit applies to the material as it is being used, there are no additional sources of the same restricted constituent in the formula, and the supplier documentation is being interpreted on the correct basis.

A 10% laboratory dilution changes the calculation

Many perfumery materials are used as laboratory solutions. In that case, the amount of solution must be distinguished from the amount of active raw material.

If you use 5% of a 10% solution in the fragrance concentrate:

5% × 0.10 = 0.50% active raw material in the concentrate.

If that concentrate is then used at 20% in the finished perfume:

0.50% × 0.20 = 0.10% active raw material in the finished product.

It is therefore incorrect to compare “5% of a solution” directly with a limit that applies to the substance or undiluted material when the document requires calculation on the active material.

Conversely, if supplier IFRA documentation has been issued for a commercial product already diluted as supplied, that supplied product is the reference. Do not recalculate it arbitrarily without first confirming the basis used in the document.

Raw material and fragrance mixture: they are not the same type of document

Another important distinction is between a limit relating to a raw material or one of its constituents and a Certificate of Conformity for a fragrance mixture.

If a complete fragrance compound has, for example, a Category 4 maximum of 18%, that 18% indicates the maximum amount of that fragrance mixture in the finished product, based on the most restrictive constituent present in the mixture.

It does not mean that every individual ingredient inside the mixture is permitted at 18%, nor that the concentrate can be reinterpreted ingredient by ingredient without the necessary composition data.

Contributions from other sources: limits are not checked ingredient by ingredient in isolation

Some substances covered by IFRA Standards can be present in several raw materials in the same formula, particularly when essential oils, absolutes, resinoids and other Natural Complex Substances (NCS) are used.

In these cases, the total contribution of the restricted constituent from all sources must be considered. If a restricted substance is present directly and is also naturally present in one or more extracts, those contributions add together and must be compared with the applicable maximum.

For this reason, IFRA publishes an Annex covering contributions from other sources. Where specific analytical data from the manufacturer or supplier are not available, IFRA documentation can provide reference values for NCS materials.

This is one reason why checking an “IFRA Cat. 4” line for each raw material separately does not replace evaluation of the complete formula.

What does “100%” mean?

When technical documentation shows Category 4: 100%, it does not mean that the perfumer should formulate with the raw material at 100%.

It means that, for that specific IFRA Standard or calculation and category, no lower maximum is produced by that particular IFRA restriction. You still need to consider:

• the olfactorily sensible dosage;
• other constituents or sources in the formula;
• SDS information and hazard classifications;
• applicable cosmetic and labelling obligations;
• subsequent updates to the Standard.

Likewise, “no IFRA restriction” does not mean “no safety or regulatory limits of any kind”. It means that no applicable IFRA restriction is identified for that context and the version of the Standards being considered.

IFRA limit and recommended dosage are two different things

This is perhaps the most important distinction for the formulator. An IFRA limit answers the question:

“What is the maximum acceptable concentration under the IFRA Standard for this category?”

A formulation dosage answers a different question:

“How much of this raw material is needed to obtain the desired olfactory effect without unbalancing the formula?”

A material can have a very high IFRA maximum and already be olfactorily effective at 0.1%. Another material may be used creatively at relatively high levels, provided the finished formula remains within the applicable limit.

The same principle is discussed in our guide to fixatives in perfumery: a technical value does not replace evaluation of the material's real function in the composition.

A solvent does not “cancel” the limit

Diluting a raw material in ethanol, DPG or TEC often makes it easier to weigh and dose, but it does not remove the amount of active material that ultimately reaches the finished product.

The dilution must therefore be included in the calculation. For more on choosing the technical vehicle itself, see DPG or TEC: which solvent should you choose in perfumery?.

A complete example

Suppose you want to create a Category 4 perfume containing 25% fragrance concentrate. A raw material has a Category 4 limit of 2.4% in the finished product.

The theoretical maximum in the fragrance concentrate is:

2.4 ÷ 0.25 = 9.6%

For olfactory reasons, however, you decide to use it at only 4% of the concentrate. In the finished product:

4 × 0.25 = 1%

The formula is therefore below the 2.4% level for that source. But the compliance check is not necessarily finished: you must still determine whether the same restricted constituent enters the formula through other raw materials.

IFRA does not replace complete regulatory compliance

IFRA Standards are an important fragrance-industry product-stewardship tool, but they do not replace the laws and regulatory requirements applicable to the finished product.

For a cosmetic product marketed in the European Union, for example, compliance also involves the requirements of the Cosmetics Regulation and related legislation, including safety assessment, the PIF, allergen management and labelling where applicable.

A formula described as “IFRA compliant” is therefore not automatically a finished formula ready to be placed on the market.

Practical workflow for checking Category 4

1. Identify the correct IFRA category according to the product's intended end use.
2. Check the current version of the Standard or supplier documentation.
3. Determine the percentage of fragrance concentrate in the finished product.
4. Calculate the real concentration of the raw material or restricted constituent in the finished product, including laboratory dilutions.
5. Add contributions from all sources when the same restricted constituent is present in more than one raw material.
6. Compare the total with the IFRA maximum for the relevant category.
7. Check separately the SDS, allergen information and regulatory requirements for the product intended for sale.

Which Amendment is currently in force?

Update: August 2026. At the time of publication, the current notified documentation remains the 51st Amendment. The public consultation for the 52nd Amendment closed on 12 June 2026, and IFRA states that formal Notification is expected towards the end of November 2026.

This means that proposals in the 52nd Amendment should not be treated as final notified Standards before the formal Notification. For commercial production, always verify the latest documentation available at the time of assessment.

Conclusion

Reading an IFRA Category 4 limit correctly means keeping finished product, fragrance concentrate, laboratory dilution and active raw material clearly separate.

The number stated in an IFRA Standard or supplier document is not a recipe and is not a recommended dosage. It is a compliance parameter that must be applied to the actual finished formula.

The right question is not “How much does IFRA allow me to put in my concentrate?” but “How much of the relevant material actually reaches the finished product, and from which sources?”

Technical note: the calculations above are educational examples and assume values expressed on the same basis. For a commercial formula, always use current supplier documentation, the current IFRA Standards and the regulatory requirements applicable to the finished product.