How the cosmetics use-by date is worked out
On a cosmetics container, the number beside the open-jar symbol followed by M marks the months the product can be used from the moment it is opened. This tool takes the date opened and the month figure printed on each product, returns the use-by date and the days left, and picks out which of several products ends first along with how many are already past their date.
The basis, and how the math runs
Under the EU Cosmetics Regulation (EC 1223/2009), this symbol appears on products whose minimum durability runs beyond 30 months, while products at or under that mark carry a best-used-before date instead. Sources split on whether that boundary reads as 30 months or more, or more than 30 months, so it is not stated as settled here. Single-use products and aerosol containers cannot carry the symbol at all. Dates are built from year, month and day components separately, so month ends and leap years hold. Figures are current as of October 2026.
Limits and disclaimer
The month figure printed on the label is the basis. No per-product month figure is offered here, and the tool makes no judgement about whether a product has spoiled. Storage temperature, sunlight and whether product is decanted all change the real condition, so follow the product sheet and the manufacturer's guidance first.
Frequently asked questions
An open jar drawn with a number and the letter M marks the months a product can be used from the moment it is opened. 6M means six months from the date of opening, not from manufacture or purchase.
Under the EU Cosmetics Regulation the symbol appears on products whose minimum durability runs beyond 30 months, while products at or under that mark carry a best-used-before date instead. Sources split on whether the boundary reads as 30 months or more, or more than 30 months. Single-use products and aerosol containers cannot carry the symbol, so none appears on them.
No. The month figure is whatever the product label states, and no per-product month figure is offered here.