Frequently Asked Questions
Everything you need to know about batch codes and expiry dates.
What is a cosmetic batch code?
A batch code (also called a lot code or lot number) is a short alphanumeric string printed or embossed on cosmetic products. Manufacturers use it for quality control and product recalls. It also encodes the date the product was made.
Where do I find the batch code?
Look on the bottom of the product, the tube crimp (the folded metal end), or on the side of the packaging box. It's usually 4–8 characters — letters, numbers, or both.
Is the batch code the same as the expiry date?
No. The batch code encodes the manufacture date. There is no legally required expiry date for most cosmetics in Canada or the USA. We calculate an estimated expiry by adding the brand's typical shelf life to the manufacture date.
How accurate are the results?
Our decoders are based on publicly documented batch code formats reverse-engineered from real products. Accuracy is high for major brands (Estée Lauder, L'Oréal, Dior groups), but some independent brands may fall back to a generic decoder with lower confidence. Always use your senses too — smell, texture, and color changes are reliable indicators of expired products.
What does "Period After Opening" (PAO) mean?
PAO is the number of months a product is safe to use after opening. Look for the open jar symbol on the product (e.g., "12M" = use within 12 months of opening). This is separate from the manufacture date expiry.
Do I need to create an account?
No. CosmeticsChecker.ca requires zero sign-up. You get 3 free checks per device. After that, a one-time $1.99 CAD payment unlocks unlimited checks forever — no subscription.
Is it safe to use expired cosmetics?
Expired cosmetics can harbour bacteria, cause skin irritation, breakouts, or infections — especially mascara and eyeliners used near the eyes. When in doubt, throw it out.
My brand isn't listed — can you add it?
Yes! Contact us with the brand name and some example batch codes and we'll work on adding it.
Why is the confidence level "low" for my result?
Low confidence means a generic decoder was used because we don't have a confirmed brand-specific algorithm. The date shown is a best estimate, not guaranteed. Check the product physically as well.