Where it's printed
For Estée Lauder, look for three characters, something like A63: a month symbol in the middle and a digit at the end. Where the mark sits varies by product; the batch code guide covers where to look.
How the code is built
The first character doesn't take part in the date, and the app ignores it. The second character is the month. It is often a digit, but letters stand for months too.
The third character is the last digit of the year. A single digit comes back every ten years, so the app picks the latest year that ends in it and isn't in the future. A 3 is 2023, not 2033.
Worked example
A63. The 6 is June and the 3 is 2023, so this product was made in June 2023. Add the 60 months the app uses for Estée Lauder and the best before date is June 2028. In November 2026, that is about 19 months left.
That is what the app hands back for this code: the date, the shelf life it applied and the months left, with no sums on your side.
Variants and edge cases
The app handles the variants and edge cases for you, including the longer strings some packs carry. Some codes the rule can't date; the app says so instead of guessing.
Shelf life and the PAO symbol
The app uses 60 months for Estée Lauder. That is a generous figure: it has no published number from the brand behind it, and Clinique, from the same group, states at least 30 months for sealed products. Treat the best before date as the outer edge, not a promise.
Once a product is open, follow the PAO symbol on the pack instead, the little open jar with a number such as 12M beside it.
Cosmetic Checker is independent and isn’t affiliated with Estée Lauder.