How to Read Cosmetic Batch Codes and PAO Symbols

Two small markings on a product answer two different questions. The batch code tells you roughly when it was made. The open-jar symbol (PAO) tells you how long it stays good once you open it. Most people mix the two up, and most people never look at either, which is how a three-year-old mascara ends up near an eye.

Batch code vs barcode

The barcode identifies the product and is the same on every unit. The batch code (also called a lot code) is a short string of letters and numbers that identifies one production run. It's usually stamped or printed on the bottom of the pack, on the crimp of a tube, or on the box. Indian labelling rules require a batch number and the date of manufacture, plus an expiry or "use before" date, on cosmetic labels.

Reading a three-character code

Several brands in the Estée Lauder group (including MAC, Clinique, Estée Lauder, Bobbi Brown and La Mer) use a short code that follows a widely documented pattern, which our batch code checker decodes:

1. First character(s): the factory. It tells you where it was made, not when.
2. Next character: the month. 1–9 for January to September, then A for October, B for November and C for December.
3. Last digit: the year. Only the final digit of the year.

So a code like A62 reads as a June production date with a "2" year digit, meaning 2022 (or, for an old product, 2012). Because the year is a single digit, the same code repeats every ten years. Context usually settles it: a product on a shelf today is almost certainly the more recent one.

Other brands use different systems: some print the manufacture date in plain text, some use a code that only the brand can decode, and some change formats over time. If your brand isn't listed in the tool, or the code doesn't decode, the brand's customer care can tell you the date from the batch number.

What a batch code can't tell you

It can't confirm a product is genuine. Counterfeiters copy real codes. A code that looks right isn't proof, but a manufacture date that's years old, or a code that doesn't match between the box and the product, is a warning sign. Our guide to checking whether a cosmetic is original covers the other checks.

The open-jar symbol (PAO)

That small icon of an open jar with a number and an "M" (for example 12M) means the product should be used within that many months of first opening. It's separate from the expiry date, which applies to an unopened product. Whichever comes first is your deadline.

These are typical guidance figures, not rules. Always follow the PAO printed on your product when it has one.

Signs a product has gone off

• A different smell, especially sour, sharp or crayon-like.
• The texture separates, becomes grainy or clumpy.
• The colour changes (vitamin C turns orange to brown).
• It stings or irritates when it never used to.

Eye products are the ones to be strictest about, since bacteria near the eye can cause infections.

Habits that help

• Write the date you opened a product on it with a marker.
• Keep products away from heat, direct sun and steamy bathrooms.
• Don't dip fingers into jars repeatedly; use a clean spatula.
• Don't add water to a mascara to revive it.

Quick answers

Can I use a product after its expiry date?

We'd advise not to, especially for sunscreen and eye products. Preservatives weaken and actives lose strength over time.

Does the batch code show the expiry date?

Usually it shows when it was made. Expiry is worked out from shelf life, or printed separately.

What if the code doesn't match any format?

Contact the brand with the code and ask. Not every brand uses a code that outsiders can read.