How the calculator works.

The calculation

For each material in a formula you enter its percentage in the finished product. Each allergen’s figure in the material (from the supplier’s allergen statement) is weighted by that level of use and summed across the formula:

A material with no figure for an allergen contributes nothing to it. Figures given as “<0.1” are taken as 0.1, an upper bound. Results are given to three significant figures, as plain decimals.

When to declare

An allergen must be declared in the ingredient list when its concentration in the finished product exceeds 0.001% in a leave-on product or 0.01% in a rinse-off product. A product at exactly the threshold does not need to declare it.

Grouped entries

Some Annex III entries cover several substances declared under one name — for example alpha- and beta-pinene are declared as Pinene, and the damascones as Rose Ketones. Their members are summed against the threshold and declared once, under the group name.

IFRA 50 or IFRA 51

Fragrance suppliers issue allergen statements against one of two lists, which the calculator calls by the IFRA amendment they arrived with:

• IFRA 50 — the 26 allergens. The original Annex III list to Regulation (EC) No 1223/2009 (26 entries here, including two that are now prohibited).
• IFRA 51 — the extended list. Annex III as amended by Regulation (EU) 2023/1545 (81 entries here). Products placed on the EU market from 31 July 2026 must label against it, and every product on the market from 31 July 2028.

Each material records which list its supplier document covers. When you calculate against IFRA 51 and a material’s data is IFRA 50 only, the calculator tells you its figures for the newer allergens are incomplete. When you calculate against IFRA 50, figures recorded for the extended list are kept but not reported.

Canada’s Cosmetic Regulations take in the EU list and follow its dates. Great Britain has not adopted the extended list, so products for the GB market still label against the original list — choose IFRA 50. Check the current position for your market.

Strictly, the IFRA 50th and 51st Amendments are IFRA’s Standards for use limits; the labelling lists are the EU’s. “IFRA 50” and “IFRA 51” are the names the industry uses for the allergen statements issued with them, and the calculator uses them the same way.

Proposition 65

Optionally, the calculator lists the California Proposition 65 chemicals declared in the materials’ documentation — beta-myrcene, estragole, methyl eugenol and pulegone are the most common in essential oils — summed the same way. Only declared chemicals appear: a chemical left blank is taken as not declared. Chemicals from other ingredients in the formula (1,4-dioxane from a PEG, for instance) can be added per calculation.

The report gives concentrations only. Prop 65 safe harbour levels are daily exposures (µg/day), so whether a product needs a warning depends on how it is used and how much is applied; the calculator makes no warning determination.

IFRA use limits

The IFRA Standards set the maximum level of a fragrance in a product by product category. Your supplier’s IFRA Certificate of Conformity gives, for each fragrance or essential oil, its maximum % in the finished product for every category. Enter those figures on the material (or paste the certificate’s table), choose the product’s category in the calculator, and each component’s level of use is checked against its maximum.

With more than one restricted component, the calculator also adds up each component’s share of its limit (% in product ÷ maximum). The total must stay at or below 100%. That is a conservative test: if two fragrances contain the same restricted material, it is then within its limit in the product too. A component with no limit entered for the category makes the check incomplete; “No restriction” on a certificate counts as no limit, and 0 as not permitted.

The category is set by how the product is used, not by its name: a body lotion is 5A, a face cream 5B, an eye cream 3, a hand cream 5C, a lip balm 1, a deodorant or body spray 2, a fine fragrance 4, a shampoo, rinse-off conditioner or shower gel 9, a candle 12. Certificates should be to the 51st Amendment, which applies to all fragrances since 30 October 2025; certificates from the 48th Amendment or earlier use a different set of categories and can’t be read against these. The 52nd Amendment is expected to be notified in January 2027.

Your data

Your materials, their figures and your calculations are stored with your account and shown only to you. A saved calculation keeps the figures it was saved with, so its report doesn’t change if you later edit a material. Fragrance names and use levels appear on a PDF only if you tick “Show the fragrance components on the PDF”. You can download everything, or delete your account and all of its data, from the Account page.

What the calculator can’t do

The results are only as good as the data entered. Is That Natural? doesn’t check the figures you enter and accepts no responsibility for errors in them, in the results or in decisions based on them; every PDF says so. Natural materials vary from batch to batch, so re-check figures when a supplier issues a new statement. The calculator doesn’t replace a safety assessment, and the IFRA check is only as current as the certificates you enter.