When do you need a new UFI?

A new UFI is required when the composition changes

The test is whether the mixture a poison centre would be told about is still the same one. If an ingredient is added or removed, a supplier substitution brings in a different substance under the same trade name, or a concentration moves outside the range you originally declared, the product on the shelf no longer matches the record the old UFI points to. At that point the fix is not a correction to the existing dossier — it is a new formulation number, a new UFI generated from it, and a fresh submission that reflects what the mixture actually contains now. Carrying the old code forward onto a genuinely different composition is the exact failure our UFI Generator page warns against under never reusing a formulation number.

An update is enough when the change is elsewhere

A long list of changes that feel significant to a marketing or packaging team do not touch the composition at all, and for those, updating the existing dossier is the correct — and only necessary — response. That covers:

• a new trade name or rebrand, including a private-label version sold under a distributor's own name;
• a change of pack size, container shape, or closure type;
• a colour or fragrance variant built from the same underlying formulation;
• a different EuPCS product category assigned to the same mixture;
• a classification correction that does not follow from a composition change.

These changes still have to reach ECHA — an out-of-date dossier is not compliant just because nobody touched the recipe — but they go in as an update to the existing record rather than a new UFI. The deadlines that apply once one of these triggers fires are set out on our guide to when a PCN update is required.

The concentration ranges that define "a change"

"The composition changed" is not judged against the exact percentage you happened to use in one batch — it is judged against the concentration range you declared in the dossier for each component. Stay inside the declared range and a batch-to-batch variation in raw material purity, for instance, does not trigger anything at all. Move outside it, in either direction, and the mixture is treated as changed even if nothing about the formula's intent has shifted. Which range applies to which hazard class, and how wide a band you are allowed to declare in the first place, is covered in full on our composition and concentration ranges page — it is worth reading before you assume a small batch adjustment is safely inside bounds.

Decision table

Where a single change touches more than one row — a reformulation that also comes with a rebrand, say — the composition change decides the outcome: generate the new UFI first, then fold the trade name update into the same submission rather than filing it separately.