There are two types of coupon barcodes (pictured).
1. UPC barcode (left). This is the old style, still around today. For businesses, the downside is that the numbers could be decoded, via code lists on the internet.
For instance, three of the UPC numbers tell what product it can be used on. If those numbers were “000” or “992”, you could use the coupon on any product by that manufacturer - not just the one in the coupon text or picture. Some people would use the coupons on cheaper products, getting a lot of things for free.
2. GS1 barcode (right). In 2011, there was a switch to this barcode for couponing. They are more difficult to decode.
If your coupon with a GS1 barcode doesn’t scan, the store may not have the new GS1 scanners. Your cashier should then enter the coupon manually.
To guard against this issue, there are still many coupons with both UPC and GS1 barcodes.
Learn about the other parts of a coupon here.